Stop 1	Stop 2	Stop 3	Stop 4	Stop 5	Stop 6	Stop 7

Well Data

All well log information from the Montana Bureau of Mines and Geology Groundwater Information Center

How Deep is the Gneiss?

Notice that the range in depth to granite is between 62 feet to 380 feet, it really shifts around throughout the valley.

(1) Lithology From To Description 83.0 108.0 RED & WHITE GRANITE

(2) Lithology From To Description 380.0 420.0 DECOMPOSED GRANITE

(3) Lithology From To Description 0.0 180.0 CLAY TOPSOIL & ROCKY FORMATIONS

(4) Lithology From To Description 374.0 377.0 SAND-WET; GRANITE

(5) Lithology From To Description 62.0 76.0 GRANITE

	Young Alluvium	Well 1: 83 ft to gneiss
	Terrace Deposits	Well 2: 380 ft to gneiss
	Old Alluvial Fan	Well 3: "Rocky Formations" from surface
	Tertiary Alluvium	Well 4: 374 ft to gneiss
	Rock (Gneiss)	Well 5: 62 ft to gneiss

How Deep Do I Need To Drill on the Valley Floor?

Notice here that gravels are quite shallow and drillers find enough viable amounts of water at shallow depths.

(A) Lithology From To Description 0.0 2.0 TOPSOIL 2.0 40.0 GRAVEL

(B) Lithology From To Description 0.0 5.0 PIT 5.0 16.0 COARSE ROCKS SAND & GRAVELS 16.0 24.0 SAND 24.0 26.0 SAND & GRAVELS

(C) Lithology From To Description 0.0 12.0 SOIL 12.0 24.0 SAND & GRAVEL 24.0 37.0 SAND GRAVEL & CLAY 37.0 38.0 WATER COARSE SMALL GRAVEL

*** All these wells are on the valley floor in the West Gallatin Alluvium.