NOTES AND QUERIES. 



07 



I 4 e 



Ml 



Upper coal-measures. 

 Middle coal-measures. 

 Pennant grit. 

 Lower coal-measures. 

 Gannister beds. 

 Millstone grit (fare well rk.). 

 Upper limestone skale"^ ( ^ 



(Yoredalc rocks). "£ « § 



Carboniferous (or moun- \- r| ? » 



tain) limestone. j ^ ' «S J 



Lower limestone shale. J ^ 

 Upper Devonian and ^ 



Petherwin limestone. 

 Middle Devonian lime 



stone and corustones. 

 Lower Devonian. 

 Tilestone. "j 

 Upper Ludlow. I 

 Aymestry limestone. [ 

 Lower Ludlow. J 

 "Wenlock limestone. ^ 

 Wenlock shale, sandstone 



and nags. 

 "Woolhope limestone. 

 Denbighshire grits, 



shales, slates, and 



Hags. 



Tarannon shale (or pale 

 slates). 



Upper Llandovery rock 

 (May Hill sandstones) 

 (Pentamerus beds), j 



o 



O p 



o 



J 



<Z1 



I o 



p-l 

 p-l 



Lower Llandovery rock. 

 Caradoc or Bala beds. 

 Upper Llandeilo flags and"! . 



limestones. f J3 



Tremadoc slates. J P 



Lingula beds. 

 Harlech grits, etc. 

 Purple slates and grits 



(St. David's). 

 Llanberis grits and slates. J> 

 Longmyud rocks. 

 Red sandstone, conglo- | 



merate of Scotland. J 



Gneiss of the Lewis 



Basalt. 



Hornblende rock. 



Porphyry. 



Felstone. 



Trappean rock (Devon and Corn- 

 wall). 

 Diallage. 



Hypersthene rocks. 



Serpentine. 



Elvan dykes. 



Greenstone (Diorite). 



Ashy slate, and Felspathic ash. 



Syenite. 



Granite. 





1 





a 



■S3 







| 



6 





• 1 



d 













a 



8 A 







Lam 

 tiai 



Scotch System of Carboniferous Rocks. 



Upper 



coal-measures 



Moor rock 



fEquivalent to 

 j British middle 

 J coal - measures, 

 j Pennant grit, 

 lower coal-mea- 

 [_sures. 



( Millstone grit 

 \ (Farewell rock). 



Upper limestones 

 Edge-coals series 

 Lower limestones 



f Upper lime- 

 | stone shale 



j (Yoredale 



l rocks), Carboiii- 

 j ferous lime- 

 stone. 



Sandstones, shales, and f T ,. 

 r» j. tt v J Lower lime- 

 Burdie House lime- < . , , 

 , stone shale, 



stone L 



Note on Pteraspis. — Sir, — I hope you will allow the following re- 

 marks, occasioned by the notices of Pteraspis in the ' Geologist' for No- 

 vember, December, and January last, a place in an early number. 



In the spring of 1861, from amongst a lot of fragments laid aside by the 

 workmen in a quarry in the hill immediately to the north of the Bridge of 

 Allan, I picked up a line head of Cephalaspis Lyelli and two tolerably 

 complete heads of Pteraspis ; and since that time I have, from the same 

 place, procured another less perfect specimen of the latter genus. To this 

 discovery I referred in a paper read to the Geological Society of London 

 in July of the same year ; and thus, I believe, I was the first to show that 

 our Scottish rocks containing Cephalaspis also possessed the nearly allied 

 genus Pteraspis. 



Of the most perfect of these three heads, both the cast and its opposite 



