238 AMEEICAN JOURNAL 



and geology of this coast. It is that the coast range, if not the 

 Sierra Nevada also, once consisted of a long group of islands, 

 the highest points only being above the sea. On these, as on 

 the islands now opposite the southern coast, species were created, 

 usually distinct on each, but closely allied, as are all inhabiting 

 such archipelagoes. As the land rose higher, these have grad- 

 ually but very sloivty extended their range, and some of them, 

 meeting, produce the hybrids which puzzle us. Others have 

 perhaps died out from the increasing dryness of climate, and 

 some may have changed their form and characters, as seen in 

 the fossils of Tryoni and facta. Yet sufficient distinctness re- 

 mains to identify most of the nominal species with certainty, and 

 further research may even separate some of them into two or more. 

 In some cases accidents may have transported specimens to 

 different localities, where they have flourished, possibly, under 

 an altered appearance. This is more likely to happen among 

 islands, especially when surrounded by fresh water, from the 

 drifting of logs, etc. ; but we do not know that the eggs thus 

 carried about may not be able to bear a short immersion in salt 

 water. But on the main land, as now existing, this is a very 

 rare accident, not even the great rivers having transplanted the 

 species from the Sierra Nevada to the coast range. The Colum- 

 bia River, however, may have thus transplanted Toivnsendiana 

 west of the Cascade mountains. 



Explanation of the Map. — This map exhibits, by straight 

 lines, the extent and direction of the range of the larger species, 

 which seem to be most limited in distribution. In most cases 

 the actual width of the region inhabited by each is not much 

 wider than that of the line, in proportion to the country it 

 passes through, on the scale of this map ; but in Oregon and 

 Washington the west base of the Cascade mountains is the east- 

 ern limit of most of them, two only passing round north of the 

 49th parallel into the Rocky Mountains. Southward of lat. 49° 

 no species have yet been found between the Cascade Mountains 

 and Sierra Nevada on the west, and the line of Ang. strigosa 

 on the east of the great interior basin, which is too arid for their 

 existence. Some of the higher mountains traversing the basin 

 may, however, be yet found to furnish specimens, especially of 

 Relic ellince. 



Most of the localities here mentioned must be sought for on 

 larger maps. The references commence at Guaymas. 



a. — H. Remondii, (Tryon), and probably near this is the 

 habitat of H. Rowellii. 



b. c. — H. Remondii, ? (Gabb), and south of b is the range of 



