INTRODUCTORY LETTER. 
Philadelphia, October 14, 1854. 
Sir : I have the honor of submitting to you the following report on the natural history of the 
country through which we passed during your late survey, commencing at the junction of the 
Colorado and Gila rivers, and continued through northern Mexico, New Mexico, and termina¬ 
ting at San Antonio, Texas. 
The general barrenness of the country lying along our route proved a considerable obstacle to 
the pursuit of my favorite branch, Ornithology ; though among the few species obtained some 
are new, and most of them rare, and concerning whose habits little was previously known. 
Of the reptiles, in which these countries are very rich, I had succeeded in forming quite a 
handsome collection, but unfortunately the cans in which they were contained became leaky, 
and possessing neither the means to correct this mishap, nor the alcohol to supply that wasted, 
they were all lost with the exception of a few specimens which I preserved in bottles. These 
have been described and classified by Dr. E. Hallowell. 
The fish, of which I had also obtained many species, met with the same fate as the reptiles. 
It is much to be regretted that so many interesting objects should have been lost through 
unforseen and, therefore, unavoidable accident. 
I remain, sir, your most obedient servant, 
A. L. HEEKMANN, M. D. 
Surgeon and Naturalist to the commcirxl. 
Lieutenant J. G. Parke, 
United States Topographical Engineers , Washington , D. G. 
