This appeal arises from the decree and judgment passed by the District Judge Cachar in TA No 11 of 19.74 allowing the appeal, from the judgment and decree passed by the Assistant District Judge (1) Cachar, Silchar, in TS No 53 of 1970. 2. The plaintiff-respondents filed the suit in the Court of Assisian District Judge (1) against the defendant appellants claiming, inter alia, a decree for declaration of title in respect of the land having an area of 59 B 9K 12 Ch and confirmation of possession o the suit land, or, in the alternative, khas possession o, the suit land if the plaintiffs are not found in possession. The case of the plaintiffs, in brief, is that the plaintiffs are owners of the land covered by 2nd RS Patta No 1)4 of Mouzi Doongripar Pt - II Pargana Sonapur, Cacbar. The river Borak was originally flowing continuous to the south and the east of the land of the plaintiffs and the river gradually receded and the suit land had gradually and imperceptibly gained to the land of the plaintiffs Therefore, the suit land was to be considered as a part and parcel of the plaintiffs' original land (pre-existing land). The plaintiffs' have been in possession of the suit land. But the Deputy Commissioner Cachar illegally issued annual Patta No 7 to the defendants 2 to 34. The defendants contested the suit denying the allegations made by the plaintiffs and stating that the settlement was made in accordance with law. 3. The trial Court has held that the suit land was added to land of the plaintiffs. However, the trial Court dismissed the suit on the ground that 'there was no prayer for cancellation of the annual patta 8 Issued in the name of the defendants concerned. On appeal, the lower appellate Court set aside the decree and decreed the suit in favour of the plaintiff-respondents by holding that the suit land gradually and imperceptibly accreted to the land of the plaintiffs due to the action of the river Borak. 4. The first question for determination is what is the law relating to the land gained by dereliction of a river. 4. The first question for determination is what is the law relating to the land gained by dereliction of a river. Explanation to section 3 of the Assam Land and Revenue Regulation, 1886, for short the "Regulation" provides : "Any land gained by alluvion or by dereliction of a river to any estate as herein defined, which under the laws in force is considered an increment to the tenure to which the land is accreted, shall be deemed to be part of that estate." (emphasis are added) Under the explanation, the land which has been gained by alluvion or by dereliction of a river to any estate shall be deemed to be a part of that estate, if under the law in force it is considered as an increment to the tenure to which the land is accreted. 5. It has riot been brought to my notice any statutory law that any land gained by alluvion or by dereliction, of a river to any estate shall be considered as an increment to the tenure to which the land is accreted. However, the proviso (c) to section 34 of the Regulation provides that any land gained by alluvion, or by dere­liction, of a river, during the currency of the settlement, increments shall be assessed by the Deputy Commissioner to such limitations as to the extent of gain and such other conditions as may be prescribed. The proviso (c) also indicates that, even if a right to land gained by alluvion, or by dereliction of a river is recognised under the law in force, the right may not necessarily be extended to the entire land accreted, i.e. the right may be limited to a restricted area only. For example, if two Bighas of land is gained by alluvion, or by dereliction, he right may be restricted to one Bigha only. But the provision under le proviso (c) shall be applicable only if and when there is any Jaw i force, as provided under the explanation to section 3 of the Regulation. 6. The question, which, therefore, arises for consideration is whether le doctrine of accretion under the law of England is applicable to le present case in the absence of any statutory enactment. 7. Dereliction may be either gradual or sudden. The present case of the land gained by a gradual dereliction of a river. 6. The question, which, therefore, arises for consideration is whether le doctrine of accretion under the law of England is applicable to le present case in the absence of any statutory enactment. 7. Dereliction may be either gradual or sudden. The present case of the land gained by a gradual dereliction of a river. Under the law of England, where the water of a river recedes or shrinks back slow the usual water-mark gradually and imperceptibly from the land thereby causing gradual and imperceptible increment of the pre-existing ad, the increment is known as land gained by gradual dereliction such a case, the result is the same as the land gained by alluvion it is alluvion in its legal sense. Alluvion is the land gained from the a or a river by washing up of sand and soil so as to form "terra firma" (firm earth). If the process is gradual and imperceptible the accretion longs to the owner of the pre-existing lands (riparian owner); if e process is sudden and perceptible, the accretion belongs to the Crown. The principles underlying the law of England is based upon impossibility of indentifying from day to day the small additions or substratum from the land caused by constant action of the physical force of the running water. 8. In the absence of statutory law on the subject, I am of the view that the principle underlying the law of England is not altogether irrelevant for consideration for the following reasons. The principle is based on the natural right or the natural advantages from its situation, and the explanation to section 3 widens the scope of section 3 of the Regulation so as to include the land gained by alluvion, or by dereliction, of a river within the meaning of estate under section 3 and therefore, the effect must be given to the legislative intent to consider the land gained by alluvion, or by dereliction of a river to any estate shall to be a part of the estate to which it is accreted not­withstanding the fact that there is no statutory law in force. This view of mine finds support from the decision of the Privy Council in Secretary of State vs. Foucar and Co. Ltd., AIR 1934 PC 17. This view of mine finds support from the decision of the Privy Council in Secretary of State vs. Foucar and Co. Ltd., AIR 1934 PC 17. The relevant portion is at pa e 19 and is as follows: "In India the doctrine has been embodied in the law of Bengal Regulation 11 of 1825, and Oudh by Act IS of 1876, and it is equally well established in Madras, where there is no statutory enactment on the subject. In Bombay the right is recognised but is restricted by the Land Revenue Code of 1879, S. 4, to accretions not exceeding an acre in extent. Under these circums­tances it would, their Lordships think, be difficult to hold, as the appellant contends, that the doctrine is wholly in applicable to Burma, where under Act 13 of 1898 the ultimate test is to be "justice, equity and good conscience." (emphasis added) 9. For the reasons stated, accretion caused gradually and imperceptibly by alluvion or by dereliction, of a river, shall be accreted to the adjacent riparian owner as a matter of natural right. However, if addition be caused suddenly or in a single season and remaining unchanged, it will belong to the State. Otherwise, it would contradict the term "gradual and inperceptible". 10. The Courts below relied on the decision of this Court in Boroji vs. State of Assam, AIR 1958 Assam 34(DB).I am of the view that my conclusion above is not in conflict with the decision of this Court. 11. The next question which arises for consideration in this case is whether there was an accretion by dereliction of the river Borak. It is a mixed question of law and fact. In the plaint, the plaintiffs have not stated the period within which the suit land was added to the plaintiffs' patta land. However, the evidence of the plaintiffs' witnesses is that the suit land was formed within a period of 15/16 years, and that the suit land had been gradually accreted to their land. As stated earlier, the addition must be gradual and imperceptible. There­fore, the plaintiffs must prove that the river Borak receded or shrank back gradually and imperceptibly and that the suit land was formed gradually and imperceptibly. It may be noted here that no issue was framed whether the suit land was formed gradually and impercept­ibly. However> parties knew their respective cases and had led their evidence. There­fore, the plaintiffs must prove that the river Borak receded or shrank back gradually and imperceptibly and that the suit land was formed gradually and imperceptibly. It may be noted here that no issue was framed whether the suit land was formed gradually and impercept­ibly. However> parties knew their respective cases and had led their evidence. ''Gradual and imperceptible" is to be proved in many ways. A mere statement of a witness that accretion was gradual and imper­ceptible without disclosing his means of knowledge, or without objective or demonstrable facts, is no evidence but is merely an expression of opinion or conclusion. 12. The evidence of the witnesses of the plaintiffs is that the suit land measuring about 60 Bighas was formed within a period of J5/16 years, and that it was formed gradually. It is a. mere statement of witnesses to the effect that the accretion was gradual. The facts from which the conclusion or inference was or could be drawn have not been stated by the witnesses. Therefore, the evidence of the witnesses that the land was formed gradually is not evidence in the eye of the law. That apart, there is no material on records to indicate that the gain was imperceptible. For these reasons, the plaintiffs have failed to prove that the suit land was formed gradually and imperceptibly. 13. In view of the 'conclusion above, I am of the opinion that it is not necessary to deal with the other contentions of the learned counsel for the appellants. 14. For the foregoing reasons, appeal is allowed. The decree of the District Judge Cachar is set aside. The suit is dismissed and the decree of the trial Court is restored with the observations above. No costs.