J. Lomas — The CrydaUine Gneisses. 537 



Geneva beach, 700 feet ; and the "Warren shoreline, about 880 feet. Another and 

 still higher shoreline exists in at least the Seneca and Cayuga valleys, hut is not 

 indicated on the map, as its east and west limits are not yet determined. This is the 

 shore of Lake Newberry, having its outlet south of the present Seneca, by the 900 feet 

 col — the Horseheads Channel. 



The Iroquois shoreline is represented as continuous, although from Sodus Bay 

 eastward it is broken and indeterminate. 



The waters producing the Geneva beach certainly occupied a large area, but as so 

 little is at present known of that lake, the shoreline is represented only along the 

 west side of Seneca valley, where it has been continuously traced. 



The Warren shoreline has been continuously traced eastward to beyond the 

 meridian of Rochester, and good spits and bars have been found in the Cayuga 

 valley. The theoretical limits are indicated as far east as the first spillway of the 

 lowering waters. 



11, — Do THE Ckystalline Gneisses kepresent portions op the 

 Original Earth's Crust ? 

 Presidential Address read before the Liverpool Geol. Soc, October 12, 1897. 

 By Joseph Lomas, A.E.C.S., F.G.S., Pres. Liverpool Geol. Soc. 



IN order that progress may be made in any branch of geology, it 

 is necessary, not only that tlie faculties of observation and 

 inductive reasoning should be employed, but a proper use should 

 be made of the imagination. By this means new lines of research 

 are laid out. The theory we set ourselves to prove may eventually 

 prove to be wrong, but it often happens that the pursuit of a false 

 theory brings one as near the truth as the following up of a true 

 one. It is in this spirit I wish you to regard the problems and 

 speculations to which I now invite your attention. 



The oldest rocks with which we are acquainted are the crystalline 

 gneisses and schists which form the lowest divisions of the Arch^an. 

 Geologists are far from being in accord as to their origin. Some 

 regard them as altered sedimentary rocks, metamorphosed to such 

 a degree, that they have been fused to form igneous rocks anew ; 

 and whilst they were in a fluid or semi-fluid condition, at a great 

 depth below the earth's surface, they received the characters of 

 foliation and schistosity which most of them show. Others regard 

 them as igneous rocks which have been altered by flow and shear. 

 Others, again, prefer to look upon them as remnants of the crust of 

 the earth when it first consolidated from the liquid state. 



They are the only rocks which can be regarded as forming 

 a continuous shell round the earth. On them, as a foundation, 

 all the later formations have been deposited. 



Professor Lapparent^ refers to the remarkable uniformity of these 

 primitive rocks. In Brittany, the Pyrenees, Alsace, Bavaria, the 

 Alps, Saxony, Scandinavia, Great Britain, SjDain, Algeria, North 

 America, Brazil, and China, and wherever they are found, the same 

 succession can be made out — gneissose or granitoid at the base and 

 schistose above. Chemically they are very much alike, except that 

 alkalies predominate in the gneissose rocks, and calcareous material 

 in the schistose. He regards them as having been produced on the 



1 " Traite de Geologie," p. 675. 



