[120] 24 



scientific proceeds of the expedition. Fendler is a collector of extraordi- 

 nary aptitude and skill, and his specimens have been pronounced to be 

 unsurpassed in perfection, 



Mr. Charles Wright started last summer from San Antonio, Texas, to 

 El Pnso del Norte^ in the southern part of New Mexico, accompatiying 

 the United States troops. He went on his own risk and that of Dr. 

 Gray, aided by an advance of $125 made up by two gentlemen of Bos- 

 ton. It is desirable to keep him in New Mexico to explore the unvisited 

 regions of it for another year at least, if not for two or three. A subscrip- 

 tion ot $150 per year for this and next year, at least, on the part of the 

 Smithsonian Institution, would be a most important contribution to the 

 advancement of Amcn'ican science, and would bring this enterprise to a 

 successful issue. The collections made during the present season in a 

 region never before visited by a naturalist are expected to come to hand, 

 and to be distributed, in the covu'se of the ensuing winter. 



Communicaiion from Professor Ag-assiz, relative to the formation of a 



Museum. 



''As you do not contemplate forming a general museum in the Smith- 

 sonian Institution, but limit yourself to preserving the specimens re- 

 ferred to in the papers published in the Contributions, and to collecting 

 materials upon some iew special subjects, I would respectfully suggest 

 that a special collection of living and tertiary shells of the United States, 

 and another of embryos and young animals of all classes, be the subjects 

 to which you direct tlie attention and care of the keeper of the natural 

 history coliections. These collections should be made with special ref- 

 erence to the solution of some most important questions now pending in 

 the study of natiu'al history. 



"Let me first point out to you the objects of a special collection of living 

 and tertiary shells. It is a problem to ascertain the mean annual tem- 

 perature of the diflerent geological periods anterior to the present condition 

 of our globe. Various estimates have been made, but they do not rest 

 upon sufficient data. Now the United States are most favorably situated for 

 the solution of this question. Tliere is a shore extending north and south 

 over more than twenty-three degrees of latitude, along which shells are 

 everyv/liere common, and present a succession of remarkable changes in 

 their distribution and mode of association from the northernmost bound- 

 aries of that zone to its southern extremity, closely connected with the 

 ditFerences of climate under whose influences they live in different lati- 

 tudes. A more minute investigation into the limits of this distribution, 

 vvhic^i has already'- been correctly ascertained by Dr. A. A. Gould for the 

 northern States, would soon show such precise relations with the climate 

 as to enable the observer to conclude from the shells the climate, (where 

 he knows only the sliells without indications upon their origin) and vice 

 versa. What renders the United States particularly adapted for such in- 

 vestigations is the fact, that there is along the same shore a belt of tertiary 

 deposites extending OA^er as wide a zone as the present seashore. In these 

 depositcs shells abound; and, \vhat is most remarkable, the older or lower 

 beds contain a greater proportion of species similar to those which at pres- 

 ent occur further south, whilst the uppermost layers contain such as are 

 still to be found alive in the same vicinity. Large collections of these 



