DAVIDSON — SCOTTISH CARBONIFEROUS BRACHIOPODA. 
467 
TV. ThoLoWERLlMESTONE-SERIES, 
about one liundrcd fathoms 
in thickness, consists of nine 
or ten beds of Umcstone; coal- 
seams of poor qualitjr ac- 
com}>anying, or rather lying 
under, the last three ; yellow 
and white sandstone, rather < 
sparingly developed ; vast 
beds of shales becoming red 
towards the base of the series ; 
fire-clay, red in colour in the 
lower beds ; numerous bands 
of ironstone — resting on the 
Old Red Sandstone. 
'Lingula-ironstone 317 fathoms. 
Lingula-limestono 337 „ 
1st Kingshaw lime- 338 „ 
stone 
2nd Kingshaw lime- 341 „ 
stone. 
1st. Calmy lime- 343 „ 
stone. 
Raes Gill ironstone 354 „ 
Hosie's limestone 356 „ 
2nd Calmy hme- 371 „ 
stone 
Main limestone 375 „ 
Shelly limestone 391 „ 
Great Prodndiis 
Q/iganteus) lime- 397 „ 
stone. 
Ironstone-bed, Pro- 400 „ 
^ ductus pundatus 
In all but the upper coal-series have Brachiopoda been found ; 
they appear, however, more numerous in the second and fourth 
divisions. 
No regular section or detailed account of the coal-formation to 
the north of Glasgow appears to exist, yet it is evident from the 
position of the strata, and the similarity of the fossils found in 
the beds, that they also occupy the same stratigTaphical position, 
as in the Carluke section, but with this important and notable 
difference, namely, that the lower marine limestones and shales con- 
taining fossils in the parish of Carluke come veiy close upon the Old 
Red sandstone, vdthout any thickness of strata intervening ; and 
this seems also to be the case all along the south-western border of 
the coal-field, while all along the north-western border the lower 
marine limestone and shales are separated from the Old Red sand- 
stone by an immense deposit made up of numerous alternations of 
thin-bedded limestones and marly shales, with one or two beds of 
red and grey micaceous sandstones, locally tenned "Ballagan-" and 
" Levenside-limestones," from the fine sections of strata exposed at 
those places.* These beds had fonnerly been regarded by some 
geologists as belonging to the uppermost member of the Old Red 
sandstone, while others referred them to the Lower Carboniferous ; 
and it was only recently, fi'om Mr. Young having in three different 
localities found fossils of a true carboniferous type, that these doubt- 
ful beds, upwards of one thousand feet in thickness, could be referred 
* I am indebted to Mr. Jolin Young for the information I possess relative to 
the strata to the north of Glasgow ; and to Messrs. Thomson and Armstrong for 
that relative to Ayrshire and the neighbourhood of Glasgow. I attach much im- 
poi-tance to these districts on account of the great care with wliich the Brachio- 
poda have boon collected, and of which we will furnish complete Ksts hereafter. 
