Transcribe Ward, Henry A. Letter to Dewey, Chester (1856-03-31)

has been (as I have before told you, chiefly according to the determinations & classifications pf Prof. Cordier. The word </u variety > ( which , by the way, I think ought to be entirely banished from Zoology, either living or fossil, and at least until Naturalists can use it more intelligently) may unquestionably be applied </s to > ^in^ the division of rocks, but I hardly think that there is need for it before their number exceeds about 200. Although the characteristic features of </u a species > are less striking at first view ^& entirely different^ in a rock than in a plant or animal, I think that they are fully as discoverable by study & rest on a certain constancy of mineral composition united to many little doubtful marks of their mode of origin. Once ^satisfied^ that such is here the distinction of species I do not hesitate to receive them from any one who can </u prove them >. The long close investigations of Prof. Cordin have signally prepared him to classify the rocks He has succeeded in separating (under a powerful microscope) each one of them into their original ^composing^ minerals, which he has then analysed. He knows by specimen from all parts of the world, who associations are constant, by what elements are, accessory. When such investigations are united to the knowledge (obtained by a geological voyage