Located less than six miles south of Dubuque and one and three-fourth miles due west of Massey station on the Chicago, Milwaukee & St. Paul Railroad are some curious "spar caves" as they are appropriately called. In these caverns are some occurrences of satin spar that are very unusual and of much interest. It is doubtful whether there is another locality where such peculiar forms of calcite are found, two varieties being associated together in the stalactites. The latter have also undergone a change in structure since first formed.
Proceedings of the Iowa Academy of Sciences
©1893 Iowa Academy of Science, Inc.
Leonard, A. G.
"Satin Spar from Dubuque,"
Proceedings of the Iowa Academy of Science, 1(Pt. 4), 52-55.
Available at: https://scholarworks.uni.edu/pias/vol1/iss4/19