[F] Telegraph Creek Formation - Montana - US
Montana - US
The Telegraph Creek Formation is a transitional unit between underlying Marias River Shale and the overlying Virgelle Formation. It is similar to the transitional unit between the Bearpaw Shale and the [Horsethief Formation] Horsethief Sandstone (Mudge and Earhart, 1983). The Telegraph Creek consists mainly of gray mudstone interbedded with fine-grained sandstone. Sandstone beds are thicker toward the top of the formation and locally are crossbedded and ripple marked (Cannon, 1996). The Telegraph Creek Formation ranges from 120 to 170 feet thick (Zimmerman, 1967).
Source: Berg (2002) Geologic Map of the Cut Bank 30\\\' x 60\\\' Quadrangle Norhwestern Montana
The Telegraph Creek Formation of southern Montana and the Telegraph Creek Member of the Milk River Formation in southern Alberta is characterised by shale and silt with some sandy beds increasing towards the top. It overlies the shales of the Colorado Group in southern Alberta, and the lower boundary is defined as the 1st (upper) White-speckled shale (Meijer Drees and Myhr, 1981), a regionally recognised interval. There is no indication of a sedimentary break within this purely marine interval. Hicks et al. (1995) appear to indicate the base of the Telegraph Creek to be 83 Ma, while Gill and Cobban (1973) talk of 85 Ma in the west, time transgressing and getting younger towards the east.
Source: Tobias H.D. Payenberg (2000) Geochronological analysis of the Pakowki and Claggett marine incursions in southern Alberta and southern Montana
Hadrosaurid indet. - Ornithopoda - Cretaceous Late Santonian