altogether leave iimioticed. It is composed of a basaltic rock 

 termed an augite-audesite, which in Tertiary time -welled iij) into 

 a crack in the earth's crust. It did not reach the surface in our 

 area, but as denudation has gone on it has become exposed in 

 inanj' parts, and has often protected adjoining rock from the 

 denudation which it M'ould otherwise have undergone. The 

 clement of picturesqueness which it must once have imparted to 

 Cleveland scenery has been to a large extent destroyed hy the 

 mining of the rock. 



Leaving the Dyke, however, I must perforce reserve myself 

 space in which to say something of one of the later stages in the 

 evolution of Cleveland scenery' — one which did not largely affect 

 its main features — and yet one which left its mark permanently 

 and indelibly on all Cleveland, except its liigher moorlands — and 

 in a niinor clegree even there also. I mean The Great Ice Age. 



Speaking in terms of Geological time the date of the Ice Age 

 was l)ut as yesterday. If we put the period of the formation of 

 the earth's ci'ust at from 50 to 100 millions of years ago, Ave may 

 place that of the Ice Age at from 50 to 100 thousand years back. 

 Indeed, some of those who are most competent to form an opinion 

 on this subject are disposed to think that the close of it may 

 piossibly have been within the last 20 thousand years ; and, 

 impressed as I have lieen Avith the evidence everywhere 

 observable in those parts of Northern Britain Avhich I have had 

 the opportunity to study, my present inclination is to agree Avith 

 such an estimate. 



With regard to the Ice Age as it affected Cleveland I Avrite 

 at a very favouraljle moment, since JNIr. P. F. Kendall, F.G.S., 

 Lecturer in Geology at the Yorkshire College, has recently done 

 a very fine piece of investigation of glacial ice-Avork in the area. 

 He laid the results of this investigation before the Geological 

 Society of London on January Sth, 1902. and the Paper then 

 read is iniljlished in Vol. LVIII. of the Journal of the Society, 

 pp. 471-571, August, 1902. The Paper is entitled "A System 

 of Glacier Lakes in the Cleveland Hills." 



On November 11th, 1898, my friend Mr. Kendall Avrote to 

 me that he had found A'ery clear evidences that Eskdale Avas a lake 

 in glacial times, held up by ice blocks at each end. " GverfloAv 

 took place by a narroAv channel cut through the spur into a loAver 

 lake about Goathland, and thence by NeAvtondale to Pickering, 

 Avhere there is a fine delta. Other lakelets occurred both south 

 and north of Eskdale, and their outlets are clearly traceable." 



