Carboniferous Period in East Scotland. 255 
seam had accumulated under less than 100 feet of water, and to show how 
small a subsidence could carry a widespread land surface so far from the 
shore as to be practically beyond the reach of land-derived sediment. 
Mr James Wright, who has made a special study of the disposition of the 
crinoid remains in the shales overlying the Invertiel Limestone to the west 
of Kirkcaldy, divides the shales into three beds each containing a somewhat 
different crinoid fauna.!' This fact he is inclined to attribute to “the dying 
out, or perhaps migration, of certain species at different times, and the incoming 
of others as conditions became favourable for crinoid life.” 
DWARFED ForMS. 
It has long been known that many of the marine forms common to the 
Carboniferous Limestones of England and Scotland are dwarfed in Scotland 
compared with those in England, as if the conditions here had not been 
congenial to their mode of life. This is doubtless due to lesser salinity, 
admixture of sediments, and nearness to shore conditions of deposit. There 
is even a striking difference in the size of the same species of brachiopod 
shells collected from the same limestone seams near the two ends of the 
Midlothian basin. Those from the quarries at the south end are markedly 
larger than those from the north end, and are easily distinguishable from 
each other. The reason seems to be, that although our individual limestones 
are very widespread and extend over nearly the whole Midland area, yet 
our fine sediments seem to have come from the north and west as if they 
were discharged from some mighty river, while the coast-lines of the island 
represented by our Southern Uplands to the south of the Midlothian Coal- 
field, seem to have afforded coarse sediments only which were deposited 
close inshore leaving a strip of clearer water between them and the muddy 
water from the river. In support of this view it is quite noticeable that, as 
the southern part of the Midland Carboniferous area is approached, the 
limestones become more numerous and individually thicker. 
ABSENCE OF LAMELLIBRANCH SHELLS FROM THE CARBONIFEROUS SANDSTONES. 
- One is struck with the almost entire absence of lamellibranch shells from 
the Carboniferous sandstones. This cannot be due to their remains having 
been dissolved out by passage of water through these permeable strata; for, 
had they inhabited the sands in the manner of our present myas, solens, 
cockles, and such sand-loving forms, their casts, or at least their burrows 
would still be apparent, as the sandstones are sometimes found riddled with 
! Trans. Edin, Geol. Soc, (1914), vol, x., part ii., p. 159, 
