120 REPORT — 1861. 



distinction bctM-een the intrusion of gi-anite veins into surrounding rocks, produced 

 merely by the weight of the superincumbent solid rocks forcing the pranite into 

 whatever cracks and fissiu-es exist in them, and the forcible ejection of lava from 

 Tolcanos. 



If it shoidd be conceded that there is no evidence that granites are eruptive rocks, 

 except passively as I have described — that there is no reason to attribute to them 

 any active energy or force in elevating strata or raising mountain-chains, for the 

 production of which effects we see other quite distinct and sufficient causes at work, 

 it only remains to inquire whether there is any reason to doubt the sufficiency of 

 the nietamorphic action of heat, pressure, and moisture, followed by slow cooling, 

 to produce granites and syenites, as well as gneiss, quartz, and mica-schist, out of 

 sedimentary rocks ; — whether granites, speaking generally and on a broad scale, are 

 not tiiie metamoi-j^hic rocks in situ in their natural position as regards other strata. 



For a reply to this inquiry, I woidd confidently appeal to the gi'eat strides lately 

 made in the geology of primitive districts, such as the whole of the north of Scot- 

 laud, in proving that the strata imtil latelj' of unlmovm origin, in vast districts, ai'e, 

 as proved by Sir R. Murchison, om* old acquaintance, the sedimentary rocks of the 

 Silurian system in a inetamoi'jjhic state. And when we see these nietamorphic 

 rocks running by insensible gradation in a thousand ways into granites, and inex- 

 tricably mixed up ■^^^tll them, the positive evidence is strong indeed that the 

 origin of all these rocks is similar ; and I think there is no negative evidence against 

 this supposition. On the contrary, I think the remarkable progxess maldug in the 

 study of the formation of minerals and rocks imder the joint influence of heat, pres- 

 sm-e, and moistiu'c, followed by slow cooling, the true nietamoi-phic condition, is all 

 favoiu-able to the position that gi-anites and all similar crystalline rocks are 

 generally to be classed as the last term of metamorjihism. 



I am fully sensible that the slight amount of subject-matter of observation, or 

 details of evidence contained in such a paper fts this, make it of little more value 

 than as a sort of pioneer in the field of inquiry — the suggestion of conclusions 

 which can only be verified or disproved by evidence of varied character, and by 

 much more extensive observations than I have been able to adduce. I shall be 

 satisfied if it may in any way contribute to more valuable and conclusive investi- 

 gation. 



On tlie Pleistocene Deposits of the District around Liverpool. 

 By Geoege H. Moeton, F.G.S. 



The author divides all the superficial accumidations of the district into the fol- 

 lowing subdivisions : — 



Pleistocene deposits. 



7, , ^,7 . , 1 Diift sand. 



JPosf- Glacial. ]jy, -^i^ „-if 



Average thickness 10 feet. 



Glacial. J 



Submarine forests. 

 Upper drift sand. 



Averag-e thickness 100 feet, j Lowe^i'driftand. 



The Lowm- drift sand is generally beneath the boulder clay where the latter is 

 of any considerable thickness. It is seen to advantage in the cliffs on the shores 

 of the Mersey, exhibiting nests or patches of gravel. There are shells : Titrritclla 

 coiiimmiis is common ; Nassa rctiadata, Ntwula oblo)iffa ; fragments oiNatica, Patella, 

 and Tellitm also occur. 



The Poidder elm/ is the dark-red clay extensively used for brick-making. It con- 

 tains numerous pebbles and boidders, which varv in size from that of a pea to im- 

 mense blocks six feet in diameter, many of them bcin^ striated and grooved by ice- 

 action. They consist of quartz, granite, syenite, porphp-y, gi-eenstone, basalt, slate, 

 limestone, and, rarely, of new red sandstone. The shell Titrritella communis is com- 

 mon, as in the underlying sands. Mactra tnmcata also occurs, with fi-agments of 

 imdetermined species. 



The U]>j}er drift sand is of limited extent, but is well developed at the south-east 



the town, No trace of shells nor any pebbles have been found. 



