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Kirtland Shale (Kk Upper Cretaceous) The Kirtland Shale is divided into upper and lower shaley members and the middle Farmington Sandstone member. The lower member is primarily gray to gray-green shale and sandy shale lithologically similar to the upper portion of the Fruitland. The Farmington Sandstone member is primarily massive to irregularly bedded sandstone with lenses of greenish shale. The upper member consists of interbedded sandstone and shale. McDermott and Attimas Formations Kma. Upper Cretaceous -(Lower Tertiary These formations are composed of andesitic debris ranging in grain size from boulder- conglomerates to clay-shale. For the purpose of this study, the formations were not separated. Quaternary Terrace Gravels (Oal. Off. OP3 and (28u Pleistocene) Terrace gravels related to the Pleistocene glaciation occur as widespread sheets in the Durango area. Within the Carbon Junction Mine area, three levels of terrace gravels have been outlined and mapped. The oldest terrace gravel is Qgl on the map, Qg2 and possibly Qgu as the next oldest and Qg3 as the youngest. Lithologically, these units are quite similar with quartzitic and gneissic boulders and cobbles contained in a clayey silt-clay matrix. The thickness of these individual units vary from 0 to 100 feet. The contacts between the various terrace gravels are generally undefined and without a • distinct contact. The terrace gravels were deposited by glacial action over many years. Thus the contacts have been subject to the weathering and erosional effects of the environment at the time of deposition. Occasionally the contact between any of the terrace gravels may be referred to as "slumping contacts". The slumping contacts found on the Carbon Junction Mine property are typical of those found in the general glacial deposition of the region. The contacts are stable transitional zones and do not form slipping planes or other contacts which have a tendency to be unstable. Roads, buildings, or other structures placed on the contacts do not have stability problems due to the integration of the materials in the transition contacts. Quaternary Alluvium (Recent) One alluvial deposit less than one meter in thickness was located on the Carbon Junction Mine property. Some extensive soil profiles were mapped and are discussed under the soils section. The U.S.G.S. (Zapp, 1949) did locate some alluvial deposits two miles northwest in the city of Durango and one mile south of the mine area, and both were proximate to the Animas River. Some alluvial units which appeared in the Johnson Report, 1982 were field checked and compared with U.S.G.S. mapping. These units were found to be terrace gravels with good soil development. General Structure The Carbon Junction Mine lies on the north flank of the San Juan Basin. The steep dips (30 degrees southeast) are a direct influence of the San Juan uplift to the north. Technical Revision 09 (v 1.0) 4-9 Revised 3/1998