Royal Physical Society. 245 



is above fifty feet thick. It would seem, then, more correct to ascribe the 

 palseontological remains found in these beds not to two different geologi- 

 cal epochs, but to one ; and' to assign their difference in character to va- 

 ried local geologico-geographical conditions. 



No locality has as yet been found on the Bathgate Hills, where the 

 connection of these strata with the Old Red Sandstone series may be 

 traced. But this is afforded on the south-western boundary of the La- 

 narkshire coal-field, particularly at Kiln-Cadzow, near Carluke. 



If, as some suppose, this part of the central district of Scotland was a 

 narrow strait having access to the sea in the Old Red Sandstone epoch, 

 the palaeontological evidence of the strata under review would seem to in- 

 dicate that, in the period immediately succeeding, the main physico-geo- 

 graphic features were a cutting off of the access to the ocean, and a gra- 

 dual increase of the land. 



Some of the trap rocks of the district seem to be of the same age as the 

 limestones. Upright stems are found in the coal strata immediately above 

 them, particularly in the celebrated Torbanehill bed. May not the Bath- 

 gate Hills, having received an elevatory movement immediately after the 

 deposition of the limestone strata, have formed a margin of the lagoon in 

 which the Lanarkshire coal-beds were deposited ? 



III. (1.) Notice of the occurrence of Apophyllite at Ratlio. (Specimens 

 were exhibited.) (2.) Sections of Lepidostrobi were exhibited. By 

 Alexander Bryson, Esq. 



Mr Bryson exhibited some beautiful specimens of Apophyllite (the 

 Tesselite of Brewster) from the greenstone quarries at Ratho, and remarked 

 that mineralogists were much indebted to the labours of Mr George For- 

 rest of Nicolson Street for this new addition to the mineralogy of the 

 neighbourhood. Mr Forrest had also found three other minerals new to 

 this locality. 



Several carefully prepared sections of Lepidostrobi and Stigmaria were 

 exhibited by Mr Bryson, as also photographs of their microscopic struc- 

 ture. 



IV. Notice of a Discovery of Diatomacese in the Marls of Waitnean and 

 Brakegoe, near Wick, Caithness- shire. By Charles W. Peach, Esq., 

 Wick. (Specimens of the Marl were distributed among the Members 

 for examination. 



The great value of the marls of Caithness has long been known to those 

 engaged in agriculture. The chemist has shown the great per-centage 

 of calcareous matter they contain, and enumerated the other constituents 

 that make up the weight of the analysis, — silex in a small quantity being 

 one of the latter. Although silex has thus been pointed out, the source 



