Address of John L, LeConte. 243 
rock evidence of which is now buried at the bottom of the 
ocean, or perhaps entirely distroyed by erosion and separation. 
Of these changes, which involved connections of masses of 
lands, no surmise could be made except through evidence to 
be gained in the manner of which I am about to speak. 
My illustrations will naturally be drawn from that branch of 
zoology with which Iam most familiar; and it is indeed to 
Pacific coast of the United States, is found in great abundance 
