STATE GEOLOGIST. ' 2* 



2. The valley of the Au Sauble river. By S. Pettibone, of 

 Ann Arbor. 



S. Brownstown, Wayne county. By B. ¥. Woodruff, of 

 Brownstown. 



Several other communications are promised, and supposed to. 

 be in progress. . 



The unpacking and labeling of the immense numbers of geo- 

 logical specimens required to illustrate the geology of all parts- 

 of the State, and complete the suites of duplicates called for 

 by the Act establishing the survey, forms no inconsiderable 

 share of the mechanical labor imposed upon, the geologist. 

 The locality of each individual specimen must be preserved, 

 from the time it is broken from the rock, through all the vicissi- 

 tudes «f bagging, transportation by hand, boxing, transporta- 

 tion by public conveyance, and unpacking; and not only this,. 

 for where a cliff presents two, or more strata successively su- 

 perimposed, it is essential for the geologist to know what fossil* 

 ijr other specimens are afforded by each straturn. Allusion is- 

 here made to the subject, for the purpose of explaining thus- 

 early, the system of permanent labels which has been adopted. 

 Every locality visited, by the geological surveyors is desig- 

 nated by a separate number. These locality-numbers form a 

 series reaching from the beginning to the end of the survey. 

 In a book of localities provided for the purpose, the precise' 

 locality corresponding to each number is stated in full, to- 

 which are added the name of the owner of the land, (when, 

 known,) the formation exposed, the fossils found, and remarks. 

 On every specimen collected is stuck a small oval piece «f ' 

 yellow paper on which is written the number designating the- 

 locality, which, in this way, is sure to be made an inseparable 

 part of the specimen. The successive strata at any locality 

 are designated by the letters of the alphabet, in all cases be- 

 ginning ^ the lowest stratum. 



The specimens collected during the past season have filled 

 over a hundred boxes, and when it is knowp that each box con^ 

 tains from fifty to one hundred specimens, some idea may be; 



