NATURAL HISTORY SOCIETY OF GLASGOW. 225 



from the long percolation of water charged with carbonic acid, had 

 been softened, so that it could be crushed with the hand. 

 As it was apparently filled with organisms, he had selected a 

 small portion for examination. After washing this, he was 

 interested to find that the material contained several rare fossils 

 characteristic of the horizon of the Campsie Craigenglen beds, in 

 the lower Carboniferous limestone series of the valley of the 

 Clyde, and these occurred in it in greater abundance than 

 he had yet met with in any other locality. One of them was 

 a Foraminifer, forming the type of a new genus, which Dr H. B. 

 Brady has named Archcedisciis Karreii, and which he (Mr Young) 

 first discovered in the shales of Craigenglen and afterwards at 

 Brockley, near Lesmahagow. It is rather rare in most localities, 

 but in this particular boulder it may be counted by hundreds, 

 and of a larger size and in finer preservation than previously 

 known. Another notable fossil which the boulder contained was 

 the plates of an American genus of Echinoderms, named MeloniteSj 

 of which two species have been recognised in British Carboniferous 

 strata — M. Etheridgeii and M. Youngii (Keeping), the plates of the 

 latter species having first been detected in Craigenglen, and after- 

 wards in one or two other localities, though rare in all. In the 

 material of the rotted boulder, however, they are abundant and 

 well preserved. Two other characteristic Craigenglen fossils were 

 also found in the material, viz., Kirkhija Eichwaldiana, an Ento- 

 mostracan, and Trochus hiserratiis, a small univalve. In the very 

 small quantity of the shale Mr Young had examined, and which 

 represented a layer of the Carboniferous old sea bottom only a few 

 inches in extent, he had found 26 species of fossils, all of which 

 he knew to occur in the Craigenglen beds. 



Mr Young then pointed out the value of Palaeontology as a 

 guide to the proper determination of the geological horizon of 

 strata, and stated, that although this boulder could not be said to 

 represent all the varied forms of life that existed over the tract of 

 the sea bottom of which it had formed a part, yet it clearly indicated 

 what was the general character of the organisms that there 

 prevailed, and the horizon of strata to which it belonged, the 

 boulder having been drifted by ice, probably, from the Campsie 

 district, or from some other tract in the valley of the Clyde where 

 strata of the Craigenglen series occur. 



