vf the Sandstone of Ayrshire. 291 



to a knotted bramble. He writes me that he has never been able 

 to meet with either any figure or description of it. He presented 

 one specimen of it to Professor Jameson of Edinburgh. 



Had the excavators of the quarry proceeded with any care, 

 branches of trees of considerable size might have been got out 

 uninjured ; but workmen are proverbially careless and indifferent, 

 and few of any length have been saved. My friend Mr.Warner 

 of Ardeer, proprietor of the quarry, had one or two of considerable 

 magnitude, both as regarded length and girth. 



I have now brought to a close my remarks on the fossil ve- 

 getables ; but I have still one specimen to notice of an altogether 

 different kind. 



On the estate of Ardeer, to which I have already alluded, there 

 is a chain of coal-pits extending from W.N.W. to E.S.E. for a 

 distance of between four and five miles. In these the dip of the 

 strata is to the S., and consequently the rise to the N., which dip 

 and rise decline on an average from the horizon about 1* in 7*5. 

 In sinking the shafts for these, the miners have, in every in- 

 stance, had occasion to pass through a stratum or bed of fresh- 

 water shells about 9 inches in thickness and of extreme hardness. 

 The matrix, in which the shells are imbedded very thickly, is an 

 impure ironstone. In speaking of this, in the ' Statistical Ac- 

 count,^ Mr. Landsborough calls it marble ; but he had fallen into 

 the error from having been told that a chimney-piece had been 

 made of it, and, on seeing the fossil, at once discovered it, though 

 too late, as the book was by that time published. 



The pit from whence I obtained the masses submitted for in- 

 spection is the north-w^esternmost of the range (or " Turf-Dyke- 

 pit'^), and the deepest, 84 fathoms (=504 feet). The shell-bed 

 in it was struck at 37 feet from the surface, while in the south- 

 easternmost (or '^ No. 7 pit"), now in the progress of shanking, 

 the miners penetrated to the depth of 15 fathoms ( = 90 feet) be- 

 fore they came upon the shell stratum, which lies immediately 

 above the ^^main coal." 



The shells of which the mass is chiefly composed, Mr. Lands- 

 borough was at first inclined to consider as the Unio Pictorum of 

 Lamarck ; but on submitting them to Dr. Fleming of Aberdeen, 

 that celebrated naturalist pronounced them to be the Unio Urii, 

 in which opinion Mr. Landsborough on further examination con- 

 curred. 



U2 



