396 



on exposure to air, and usually containing portions of plants and other 

 organic substances iucnisted with carbonate of lime." 



Tvfaceous. A texture of rock like that of tuff. 



Tuff or Tufa. "An Italian name for a volcanic rock of an earthy 

 texture." 



Unconformable. See conformable. 



Veins. Cracks and fissures in rocks filled with stony or metallic 

 matter. Most of the ores are obtained from metallic veins. 



Zoophytes. Coral sponges and other aquatic animals allied to them. 



BE PORT of Doctor John Wright, Botanist of the Geological 



Survey. 



Detroit, January 1st, 1839. 



To Douglass Houghton, State Geologist: 



Sir: In compliance with the act passed by the State Legislature, 

 Maich, 18.38, providing for a geological survey of the State, the under- 

 signed respectfully submits the following 



REPORT: 



The examinations in the botanical department of the survey, during 

 the past season, have been made in the two most southern ranges of 

 counties of the State, from the Detroit River to Lake Michigan, except- 

 ing the county of Monroe; and in St. Clair county. 



The extensive requisitions of the bill, making it obligatory on those 

 engaged in investigating the natural history of the State, to collect and 

 preserve as far as practicable, seventeen specimens of each kind of its 

 products, has been the principal inducement for confining the sphere of 

 action to the above mentioned portions of the State. The bulky appa- 

 ratus necessary to be c; nveyed from place to place, during the excur- 

 sions', for the preservation of the plants in such extensive collections, 

 and the requisite conveniences for drying and protecting them, render 

 it impracticable to examine a very great extent of country, and particu- 

 larly such portions of it as are unsettled, during a single season, or until 

 the principal mass is collected. 



