The Boy Geologist was published by Altemus beginning in 1907. Initially it was a non series book (http://www.henryaltemus.com/images/NS_26.htm). In 1910 it was added to the Little Men and Women Series.

It has been seen with two different covers. One that has white lettering and another with black lettering. The black lettered books have advertisements for 1911 books and thus are the later books. The interiors of the books are identical.

Non Series book 1907

Series 125 book 1910