STATE GEOLOGIST. 33 



ship of London, near Dundee. Mr, \V. P. Christiancy also con- 

 tributed some instinctive Bpecimei 



Thomas Crawford, Esq., of Detroit, has laid mc under many 

 obligations for polish Linens of marble from his qnarrj 



near Pies. pie l>lc ; as also for some unique fossils from the 

 same. 



Mr. M. I). Hess, of East Saginaw, has supplied some desirable 

 altitudes from the vicinity of Saginaw. 



Thomas l-Yazer, Esq , of the Mich. C. R. R. office, in Detroit, 

 has communiated the altitudes of the principal stations along 

 the line of that road. 



Superintendent \V. K. Muir has furnished a list cf altitudes 

 of all the stations along the Detroit and Milwaukic railway, ac- 

 companied by other valuable observations. 



Chief Engineer, John B. Frothingham, of Toledo, has also 

 promised t«> supply me with altitudes along the Michigan South- 

 ern Railroad. It is hoped that such statistics will be further 

 communicated by Engineers, and others, to whom they are ac- 

 ble. 



I am indebted to the late John Farmer for a copy of the large 

 edition of his nneqnaled map of the State, and to Benjamin 

 Fowle, Esq., for a mounted map of Hillsdale county. 



Mr. John Holcroft, Superintendent of the Woodville Coal 

 Mine furnished mc with numerous data, and other facilities, 

 while investigating the coal formation of Jackson county. 



Mr. C. ES. Hovcy, Superintendent of the Eagle Plaster Co., of 

 Grand Rapids, provided me with a liberal quantity of samples 

 of the crude and manufactured gypsum, including some orna- 

 mental va 



Capt Maiden, keeper of the light house at Thunder Bay Isl- 

 and, furnished mc with some interesting specimens from the 

 Huron Group, lie is no^ d iu a Bei i< b of m< teorological 



and tidal obscrvati portance. 



i under obligations to ?erv many of our citizens for ac- 

 con ■ me on my explorations, and conveying mc to local- 



