Geology of Massachusetts. 3 
racy. IfI have not misunderstood my commission and instructions, 
I was to have principally in view, in my examinations, practical utility ; 
not neglecting, however, interesting geological facts, which have an 
important bearing upon science. Under such impressions I have 
gone over the State as rapidly as seemed to me consistent with the 
accomplishment of these main objects. In attempting to construct 
such a map as is appended, in the time that has been devoted to the 
survey, I am not without fears that I shall be thought to have aimed 
at too much; or that it will be supposed, little dependence can be 
placed upon it. Had I not previously become acquainted with the 
geology of nearly one half the State, from my own observation, or 
the published accounts of Professors Dewey, Webster, and the Da- 
nas, I should not have been able to accomplish this object, with any 
confidence in the correctness of the results. And as it is, ] am aware 
that the map may need several minor alterations ; though I feel quite 
confident of the correctness of its leading features. ‘To obtain such 
corrections before the completion of the contemplated map of the 
State, is one strong inducement, thus early, to present this Report, and 
the accompanying map. For, should the Report in any way be 
made public, I shall hope that gentlemen of intelligence, in different 
parts of the State, will do me the favor to communicate any errors, 
or omissions which they may notice. 
I propose to divide my Report into four parts. The first part will 
embrace the Economicat Grotoey of the State; or an account of 
our rocks, soils, and minerals, that may be applied to useful purposes, 
and thus become sources of pecuniary profit. 
The second part will embrace our TopocrapuicaL GroLoey; or 
an account of the most interesting features of our scenery. 
The third part will consist of our Screntiric Geouoey ; or an 
account of our rocks in their relation to science. 
The fourth part will consist of catalogues “ of the native miner- 
alogical, botanical, and zoological productions of the Commonwealth,” 
so far as they can be obtained; agreeably toa resolve of the Legis- 
lature, approved by your Excellency, February 2, 1831. Several 
gentlemen distinguished for their attainments in natural history, have 
generously offered to furnish these lists in these branches with which 
they are most familiar. 
To illustrate the first and third parts of the Report, 1 have in ac- 
cordance with directions from your Excellency, collected specimens 
of every variety of rock I could find in the Commonwealth; and in 
all cases where a rock is quarried, or might be quarried in several 
