102 , REPORT — 1861. 



presented iu Edinliui-ghsliire, and wliicli in Lanarkshire seem to graduate upwards 

 into the Lower Old Red or Cephalaspis sandstone, are wanting in the Highlands ; 

 thus accounting for the great break which there occurs between the crj-staUized 

 rocks of Lower Silurian age and the bottom beds of the Old Red Sandstone. 



Of the Old Red Sandstone of Scotland and Herefordshire I may be permitted 

 further to observe, that its downward passage into the uppermost SUiuian rock, 

 and the upward passage of its higher strata into the Carboniferous strata, have been 

 well developed, — the one near Ludlow, chiefly through the labours of Mi'. Light- 

 , body ; the other in Scotland, through the researches of the Government Geologists, 

 Howell and Geikie, as well as by those of AL-. D. Page and other observers. On 

 this head I may, however, note, what my contemporaries seem now to admit, that 

 the removal of the Caithness flags and their numerous included ichthyolites from 

 the bottom of this group, and their translation to the central pai't of the system, as 

 first proposed by myself, is correct. Li ti'uth, the lower member of this system is 

 now imequivocaUy proved to be the band with Cephalaspis, Pteraspis, &c., as seen 

 in Scotland, England, and Russia. The gi-eat break which has been traced in the 

 south of Scotland by Mr. Geikie between the lower and upper Old Red is thus in 

 perfect harmony with the zoological fact that the central or Caithness faima is 

 entirely wanting in that region, as in England — as it ia indeed in Ireland, where a 

 similar break occurs. 



It gratifies me to add, that many new forms of those fossil fishes which so pecu- 

 liarly characterize the Old Red Sandstone, have been a<lmirably described by Sir 

 Philip de Grey Egerton in the 'Memoirs of the Geological _Sur\-ey;' and I must 

 remark that it is most fortuf5ate that the eminent Agassiz is here so well repre- 

 sented by my distinguished friend, who stands imquestionably at the head of the 

 fossil ichthyologists of our coimtry. 



Very considerable advances have been made in the development of our acquaint- 

 ance'with that system — the Carboniferous — which in the North of England (York- 

 shire) has been so well described by Professor PhiUips, and with which all practi- 

 cal geologists in and around Manchester are necossamy most interested. The close 

 researches of Mr. Binney, who has from time to time thrown new light on the 

 origin and relations of coal and the component parts of its matrix, established 

 proofs, so long ago as 1840, that great part of oiu- coal-fields was acciimulated under 

 marine conditions ; the fossils associated with the coal-beds being, not, as had been 

 too generally supposed, of fluviatHe or lacustrine character, but the spoils of marine 

 life. Professor Henry Rogers came to the same conclusion with regard to the 

 Appalachian coal-fields in America in 1842. Mr. Binney believes that the plant 

 SigiUaria grew in salt water ; and it is to bo remarked that even in tho so-caUed 

 "freshwater limestones" of Ardwick and Lc Botwood, the SpirorUs and other 

 marine shells are frequent, whilst many of the shells tenned Ci/pris may prove to 

 be species of Cythcre. Again, iu the illustrations of the fossils which occiu- in the 

 bands of iron-ore in the South Welsh coal-field, Mr. Salter, enteiing particidarly 

 into this question, has shown that in the so-called "Unio-beds" there constantly 

 occurs a shell related to the Mya of our coa.sts, which he temis Anthracomya ; 

 whilst, as he has stated in the ' Memoh's of the Geological Siurvey,' just issued, the 

 very Unios of these beds have a peculiar aspect, diflering much from that of true 

 fres'hwater forms. They have, he says, a strongly wiinkled epidermis, which is a 

 mark of the Myadse, or such burrowing bivalve shells, and not of true Unionidse ; 

 they also differ in the interior, as shown by Professor W. King. Seeing that in 

 these cases quietly deposited limestones with marine shells (some of them indeed 

 of estuary character) rest upon beds of coal, and that in many other cases purely 

 mai-ine limestones alternate frequently with layers of vegetable matter and coal, 

 may we not be led to modify the theoiy, founded on the sound observation of Sir 

 W. Logan, by which the fonnation of coal has been rather too exclusively refen-ed 

 to teiTestrial and freshwater conditions ? May we not rather revert to that more 

 expansive docti-ine, which I have long supported, that different operations of nature 

 have brought about the consolidation and alteration of vegetable matter into coal ? 

 In other words, that in one tract the coal has been formed by the subsidence in situ 

 of vast breadths of foi-mer jimgles and forests ; in another, by the transport of 

 vegetable materials into marine estuaries ; in a third case, as in Russia and Scot- 

 land (where purely marine limestones alternate with coal), by a succession of oacil- 



