24 The West American ScienHsf. 



hot reg-ions, o-enerally growing in rocky or sandy situations 

 exceedingly dry, but a few are said to be found near the coast, or 

 in salt marsh districts. Only one species, M. Communis, is in 

 general cultivation, and as a curiosity it is remarkable. 



A high temperature, very porous soil, abundant drainage, and 

 little water are the chief points requiring attention in its culture, 

 and when a plant assumes an unhealthy appearance water must 

 be withheld. 



Turk's Cap, Englishman's Head, and Pope's Head are some 

 of the popular names that have been applied to this plant, all 

 referring to the peculiar crown on the summit of the stem, a 

 character by which it is easily recognized. It is found in several 

 of the West Indian Islands, particularly on the island of St. Kitts, 

 where it grows in large quantities in barren, rocky districts. 

 Specimens exceeding a yard in diameter are not uncommon, and 

 some are reputed to be two or three hundred years old. Cattle 

 and mules are said to eat the plants after removing the spiny 

 outer portion with their hoofs, as the fleshy substance of the stem 

 affords a welcome supply of moisture. C. R. Orcutt. 



THE STUD V OF RIVER GEO LOG Y. 



I wish in this paper to say something to those of you who are 

 simply beginners in the study of geology, but who have taken 

 such an interest in the work as will lead you beyond the illustrated 

 text-book and the comfortable fireside into the field. 



There are few students who are not bewildered upon their 

 first entrance into field work with the question of just what to 

 study, and yet almost all of such inquirers are living at least 

 within easy walking distance of a river or small stream, and a 

 careful study of the phenomena to be observed here will give a 

 clear insight into several features of perhaps the most fascinating 

 branch of Geology — the dynamical; and here instead of detailing 

 some of the results of past study in this direction, I wish to out- 

 line for you the manner in which you can set to work for your- 

 selves. 



As a general rule a river, considered as a whole, consists of 

 the bed, or that part occupied by the streani at ordinary stages 

 of the water, which is defined on either side by the level alluvial 

 flood plain, which is only covered at time of high water, and in 

 many cases there are constructions called terraces, similar to 

 the flood-plain in general character, at various elevations on the 

 sides of the valley which make it evident that the stream has at 

 some time been running at a higher level than at present, and 

 has been deepening its bed in the course of past time as rivers 

 are doing to-day. 



Now, in the first place, you will discover all you can of the 

 ])hysical geography of the country which the stream drains; n )t- 



