No. 216.] 667 



that botanists engaged in the researches of the sciences, be permitted 

 to examine the collection at pleasure, and in such manner as may con- 

 duce to the development of the species of plant contained in it, 

 always subject to the dispositions of the institution. 



A memorandum accompanies the package, pretty fully explaining 

 the manner in which the plants have been put up, etc. The labels 

 attached to each specimen, show the localities and dates of their col- 

 lection. It is, therefore, needless to add anything here, in explana- 

 tion or apology for the very rude and imperfect style in which the 

 plants have been preserved; in consequence, as well of inexperience, 

 &c., as of very rapid marching during the period of the collection 

 of most of them. However, I might here note in general terms, that 

 the collections were made from Chihuahua to Metamoras, along the 

 route of Parras, Saltillo, Monterey, Carmargo, &c The total num- 

 ber of species embraced, I think to be about five hundred. 



Supposing they might, in some degree, contribute to the elucida- 

 tion of the species of plants, I have accompanied a number of sam* 

 pies of the wood of many of the trees included among the dried spe* 

 cimens of leaves and flowers; also some seeds for the same purpose, 

 as well, also, that if any of them should be thought worth planting, 

 they might be used in this way. 



I had a collection of most of the kinds of rock found in the vici- 

 nity of Monterey, Saltillo, and some other places, but these have by 

 some accident, been mostly lost. With the very few remaining spe- 

 cimens, I have sent samples of ores from two mines, one iu Chihua- 

 hua, the other in Durango. What is perhaps worthy of note in the 

 mines of this part of Mexico, is that east of the dividing Cordille- 

 ras, they are nearly all plomosos, (as expressed by the people,) that 

 is, producing metal mixed with lead, but not with gold; whereas, 

 those west of the Cordilleras contain little or no lead, and have ge- 

 nerally a valuable admixture of gold. And, with regard to the geo-' 

 logy of the country, there is, at least, one very remarkable feature, 

 emphatically from Monterey to Saltillo and Parras, and that is, the 

 position of the strata, which are seldom seen at an angle of less than 

 45° to the horizon, and often perpendicular. In the very streets and 

 principal squares in the city of Saltillo, we note the surface singu- 

 larly listed with the exposed edges of different colored strata. 



If these collections should chance to afford the slightest interest or 

 satisfaction to any member of your institution, or out of it, if deem- 

 ed worthy by you, I shall feel very much gratified. 



