205] W. B. Clark Y 



At the present time nearly every State in the Union is also 

 carrying on its own official work,, generally with some form of 

 cooperation with the Federal organization. 



The State Geological Survey of Maryland, as at present 

 organized, began its operations in the spring of 1896 and is 

 thus over twenty years old. 2 Like many other similar organi- 

 zations the Maryland Survey is carried on in conjunction 

 with the geological department of its leading University. In 

 States where State universities exist they are often the head- 

 quarters of such work. 



The primary object of a geological survey is to determine 

 and describe the geological formations and depict the results 

 on maps. In order to classify these formations intelligently 

 one must establish criteria for their discrimination based not 

 only on their original lithological and paleontological charac- 

 teristics but also on their often highly changed texture and 

 structure. In such a region as Maryland, which has repre- 

 sentatives of many types of rocks, nearly every phase of geo- 

 logical investigation is involved. For this reason it affords a 

 magnificent field of study for the student and has been so 

 employed in the training of several score of graduate students 

 at this University. The State also benefits in that it has at 

 its command many trained or partially trained men without 

 the expense of a permanent staff. 



The differentiation of geological formations and their repre- 

 sentation on maps has passed through many interesting phases, 

 and a few words in this place regarding the history of geo- 

 logical maps may not be inappropriate. As far back as the 

 end of the 17th century a scheme for depicting the mineral 

 products of a country upon a map was submitted to the Eoyal 

 Society of London and appears in the Philosophical Trans- 

 actions under the quaint title of " An ingenious proposal for a 



2 The Ducatel- Alexander Survey came to an end in 1842 and tho 

 only official State geological work of any importance carried on in 

 Maryland after that time until the organization of the present 

 Survey was by Philip T. Tyson who as State Agricultural Chemist 

 from 1858 to 1862, prepared the first geological map of the State. 



