DETAILED RECORDS. 21 7 
Jordan : Feet. 
White sandstone 1, 180-1, 200 
While to gray sandstone, more or less limy 1 , 200-1, 250 
Brownish sandy limestone 1 , 250-1 , 280 
No sample 1, 280-1, 400 
St. Lawrence and Dresbach: 
Gray shaly and sandy limestone 1 , 400-1 , 420 
Brownish shaly limestone 1, 420-1, 440 
Greenish-gray limy shale 1 , 440-1, 500 
Gray limy shale 1, 500-1, 520 
Dark limy shale 1, 520-1, 540 
Brownish shaly limestone 1, 540-1, 550 
Dark limy shale. 1, 550-1 , 570 
Dark brownish-gray and gray sandy and limy shale 1, 570-1 , 590 
"I am inclined to think that 'No sample' to, perhaps, 1,440 feet will include all of St. 
Lawrence. Then greenish-gray limy shale most probably is Dresbach." — E. O. Ulrich. 
465. Well at Letts, Louisa County. 
[Well begun and completed in 1905. Authority, W. W. Wagner, owner. Samples preserved. Log 
compiled from samples by S. Sanford. Geologic correlations by E. O. Ulrich.] 
This record, though fragmentary, is of interest from its depth. Many of the samples were 
washed, making identification of the material penetrated difficult. This particularly 
applies to the recent and Pleistocene deposits, down to 325 feet. The formations below 
are Devonian and Silurian limestones and Maquoketa shale, "Trenton" limestone and St. 
Peter sandstone, of Ordovician age. 
Record of well in the SW.\ NW. \ sec. 6, T. 75, R. 3. 
Feet. 
Clay, sand, gravel, and bowlders 0- 325 
Devonian and Silurian: 
Gray limestone 326- 332 
Medium coarse brown sandstone 332- 342 
Brownish limestone 345 
Medium coarse brown sandstone 359 
Brownish limestone 362- 383 
Brownish and grayish f ossiferous limestone 385- 440 
White to brownish limestone 443 
White limy sandstone 446 
Buff sandy limestone 463 
Brown, white, and gray crystalline limestone 468- 545 
White fossiliferous limestone 578 
Brownish and greenish sandy limestone 620 
Brownish limestone 650 
Maquoketa: 
Gray and brown limy shale 720- 818 
" Trenton:" 
Grayish and buff crystalline limestone 818- 855 
White and brownish limestone 860 
Reddish crystalline limestone 875- 900 
Brown, white, and gray cherty limestone 913-1 , 000 
White, gray, and brown crystalline limestone 1, 025 
Brownish fossiliferous limestone 1, 048 
Brownish and grayish fossiliferous limestone and gray shale 1 , 063 
Brownish limestone 1, 080-1, 095 
