634 FOURTH REPORT — 1834. 



at the bottom of which these marl-strata were formed, was not of 

 tlie same depth as that part of the ocean where the thick beds 

 of limestone south of the Tweed have been deposited, he did not 

 venture to say. But Mr. Milne remarked that it was a confir- 

 mation of this view, that the same fossil trees which are found 

 in the marl-beds do not occur further south, as they would not 

 probably be drifted very far from the shores whereon they grew. 

 Besides, it is well known that currents and eddies at the bottom 

 of the sea are more frequent along the coast and the mouths of 

 large rivers than at a distance from land ; so that the same 

 cause might serve to explain the formation of those wedge- 

 shaped sandstone strata in the thick beds of clay and marl fre- 

 quent on the banks of the Tweed, as well as the gravelly conglo- 

 merates, where are seen mixed up together not only fragments 

 of various rocks, but vegetables, small shells, and fishes' teeth. 



Another deposit derived from the marl strata just described 

 consists of lacustrine deposits of shell-marl. There are several 

 of these worked on account of the calcareous matter which they 

 afford, to be spread over the land for agricultural purposes. On 

 the estate of Kimmergham near Dunse, (the property of James 

 Bonar, Esq.,) there is a mass of this nature about seven acres 

 in extent. There is at the surface a covering of peat, which, 

 in some places, is ten feet deep. Below this there are two beds 

 of white calcareous marl filled with minute shells, the beds 

 being separated by a stratum of blue clay. Each of the beds of 

 marl is about six feet in thickness. The shells found in them seem 

 to be of exactly the same genera as those found by Mr. Lyell 

 in the lacustrine deposits of Forfarshire, the Planorbis, Lym- 

 ncea, &c. In addition to these shells, remains of the beaver, 

 and of a large species of deer, were some years ago discovered 

 in this bog. The remains of the beaver, it is believed, are now 

 in the museum. A specimen of the horns found in the moss 

 was exhibited, together with portions of the marl, containing 

 multitudes of minute shells. 



In the parish of Merton, where a shell-marl moss of 100 acres 

 occurs, horns of the same species of deer were found, as well as 

 the remains of beavers. These horns were pronounced by Sir 

 Humphry Davy to belong to an extinct species. 



IV. The only remaining formation in the district is the trap, 

 which in Berwickshire, as in most other districts, may be di- 

 vided into three kinds, according to the epochs at which it was 

 successively ejected. 



1. The older trap occurs, as has been already mentioned, not 

 only in large amorphous masses among the grauwacke strata, 

 but also occasionally alternating with these rocks, and assuming 



i 



