1873.] 



JTTDD THE SECOND AET KOCK8 OE SCOTLAND. 



165 



The fossils of this rock, as is the case with those of so many of 

 the Secondary beds of Sutherland, are often much distorted by 

 pressure. 



The bed was formerly quarried on the shore, and its more calca- 

 reous portions, which are almost wholly made up of shells, burnt 

 for lime ; but this use of the rock has long been abandoned. Portions 

 of the bed too have been blown up with gunpowder, where it rises 

 as a reef on the shore, in order that the coal-bed below it might be 

 worked at low water. When the mines at Brora were in operation, 

 considerable quantities of the rock were brought to the surface ; and 

 its fossils could then be easily obtained. The only points at which 

 I have myself been able to see this rock and collect its fossils are 

 the Inverbrora reefs and the mine at Strathsteven ClhT. 



Sir Eoderick Murchison appears to have regarded this bed, from 

 its relation to the series containing the Coals, as the equivalent of 

 the " Grey Limestone " (or " pier-stone " as he calls it) of Scarbo- 

 rough*, a bed which is now very generally admitted to form part of 

 the Inferior Oolite. The true position of the " Roof-bed," however, 

 was more correctly defined by Mr. Alexander Robertson in 1846 to 

 be that of the " Kelloway Rock" of the Yorkshire coast. The an- 

 nexed list of fossils will serve to satisfactorily establish this corre- 

 lation, and to demonstrate the close parallelism which exists be- 

 tween this part of the series in Scotland and its equivalents in 

 England. 



Fossils of the " Roof -bed " of Brora (" Zone of Ammonites callo- 

 viensis " of Dr. Wright). 



Belemnites Owenii, Pratt, var. Puzo- 

 sianus, D'Orb. 



, var. tornatilis, Phil. 



Ammonites Gowerianus, Sow. 



sublaevis, Sow. 



Kcenigi, Sow. 



' S P\ 



Rostellaria composita, Sow. 



Alaria, sp. 



Actseon retusus, Phil. 



Cerithium muricatum, Sow. 



Pholadornya Murchisoni, Sow. 



acuticosta, Sow. 



Anatina undulata, Sow., sp. 



Gresslya peregrina, Phil., sp. 



Myacites recurvus, Phil., sp. 



securiformis, Phil., sp. 



calceiformis, Phil., sp. 



Thracia, sp. 



Goniomya v-scripta, Sow., sp. 



Cardium striatulum, Sow. 



cognatum, Phil. 



Crawfordii, Leckenby. 



Cardium, spec. nov. 

 Isocardia tenera, Sow. 



nitida, Phil. 



Cypricardia, spec. nov. 

 Unicardium depressum, Phil., 

 Nucula, sp. 

 Corbula obscura, Sow. 



oxfordensis, If Orb. 



Astarte minima, Phil. 

 CucuLhea concinna, Phil. 



minima, Leckenby. 



Area, spec. nov. 

 Lucina lirata, Phil. 



pulchra, Bean. 



Trigonia elongata, Sow. 



rupellensis, D'Orb. 



irregularis, Seeb. 



Modiola cuneata, Sow., var. 



bipartita, Sow. 



imbricata, Sow. 



Lima duplicata, Sow. 



, sp. 



Pteropterna, spec. nov. 



* Vide Trans. Geol. Soc. 2nd Ser. vol. ii. part 2, p. 297, where Murchison 

 clearly explains that what he identified the roof-bed of Brora with is the bed 

 now usually designated tho Grey Limestone of Scarborough. • 



