•ii Mr. Ferguson on the 



The deposit at the other point, namely, Moreseat, was said to consist 

 of a calcareous saud, visibly stratified, of a greyish hue, and also com- 

 posed of comminuted shells. This I have also had examined, and have 

 received specimens of a grey friable sandstone, not water-worn, and 

 containing shells of various genera, such as Cardium, Terebratula, 

 and Trochus. My informant writes of these : — " I went to Moreseat 

 and got some shells in a kind of sandstone. The stones they are to be 

 found in, are in a broken state, among clay of the same colour as the 

 stones, with another substance I have sent you." This seems to be a 

 fuller's earth. He does not say any thing of the stratification, nor of the 

 calcareous sand. From the friable texture of these specimens, and the 

 fragile nature of the enclosed shells, it appears obvious that the deposit 

 either is in situ, or at least cannot be far removed from it. Several of 

 the specimens are well marked with the small green grains of silicate of 

 iron, or chlorite, which has given the name of greensaud to this the lowest 

 member of the cretaceous group. It is seen at Moreseat in two places. 

 It was first discovered in digging a pit for the water wheel of a threshing 

 mill. It is nine feet below the surface of the soil, and seemed deep, but is 

 now covered up. About 400 yards from this point, it was also opened 

 up in making a ditch, and there it is only three feet below the surface. 

 The locality is on the side of an eminence. There is a thin layer of a 

 brown substance like fuller's earth. The shells are in fragmentary sand- 

 stone nodules, all presenting a broken appearance, and mixed with a half 

 sandy half clayey substance of the same colour. The fragments are very 

 soft when newly dug, but harden on exposure to heat, and turn lighter in 

 colour in drying. My specimens were dug from the bottom of the ditch, 

 and with difficulty, for the water filled the hole very fast. This prevented 

 very accurate observation of the nature of the bed. 



It may not be uninteresting now to review what has been observed 

 and theorized, with respect to the formation of flints. They occur in the 

 highest bed of the cretaceous group found in this country, which from 

 their presence has been named the chalk with flints. It covers a very 

 large portion of the south-west of England, reaching as far north as 

 Flamboroughhead,* but has not been satisfactorily proved to exist in 

 Scotland. t " The chalk of this subdivision," (says Dr. Mantell, Geol. Sur. 

 of S. E. of England, p. 73,) " is generally of a purer white, and of a softer 

 texture, than the inferior strata, but in other respects presents no sensible 

 diS'eronce. It is regularly stratified, and partakes of the general inclina- 

 tion of the other divisions of the series. It is separated by horizontal 

 layers of siliceous nodules, into beds that vai'y from a few inches to 

 several feet in thickness, and which in some localities are traversed by 

 oblitjuely vertical veins of tabular flint, that may be traced for many 

 yards without interruption. These are sometimes disposed horizontally, 

 and form a continuous layer of thin flint of considerable extent. The 



* Ansted, I. p. 455. f Ibid. p. i'lS. 



