ABSTRACTS AND DISCUSSIONS OF PAPERS 405 



STRUCTURAL FEATURES OF THE TSfN LI^IG l^HA Y 

 BY GEO. D. LOUDERBACK 



(Abstract) 



This paper includes notes on sections observed; comparison witii routes of 

 former expeditions. The inner zone ; crystalline complex, development of iso- 

 clinal folds; general effects of granitic intrusion. The Mesozoic overlap. The 

 southern zone of thrust. Late Mesozoic or early Tertiary faulting. Late Ter- 

 tiary or Quaternary faulting. Structural relations of the loess. Rt'.sume of 

 the recognized diastrophic history taken as characteristic of central China, 

 and general comparisons with the diastrophic history of the Pacific States of 

 America. General comparison of results with those of earlier expeditions. 



Presented by title in the absence of the author. 



CERTAIX STRUCTURAL FEATURES IN THE COAL FIELDS OF yEW MEXICO 



BY CHARLES T. KIRK " 



(Abstract) 



In the Number 4 Anthracite mine at Madrid, New Mexico (Upper Mesa- 

 verde), there occurs a thrust-fault of northerly strike with the astonishingly 

 steep dip of generally 85 degrees westerly, the upthrow being on the west side. 

 Within a thousand feet of where this fault is best exposed in the woi-kings is 

 another somewhat local normal fault of northwesterly strike with the aston- 

 ishingly flat dip of generally only 6 degrees southwesterly, the upthrow l>eing 

 Du the northeast .side. The country flanks on the Ortiz Mountains and is fur- 

 ther affected by sills and perhaps other igneous bodies. Surface agencies have 

 so altered the outcrops of these faults — if they ever appeared at the surface — 

 that they may not now be studied there; but workings have progressed suffi- 

 ciently to warrant an explanation of the former by suppo.sing a radial lift, 

 probably during intrusion, and i)f the latter by a tangential stretch, probably 

 during cooling of the same or a neighboring magma. The .strata and sills dip 

 14 degrees easterly in both cases, .so that the faults act as artesian chainiels. 

 and both bring up nuich incombustible gas, presumably carbon dioxide, and 

 some combustible gas, apiiarently cai'bon monoxide, both probably from car- 

 bonaceous beds below. The first was cut inexpensively by noting that the 

 (igneous) roof rock is underthrust in the face of the entry; the second re- 

 vealed its hidden nature only by bits of drag. 



In the Heaton mine at (Jil)son (dallup District), New Mexico, is a fault 

 cutting the Number 5 coal bed (Upper Mesaverde) and offsetting it l.'4 feet 

 vertically ; yet 00 feet above the Number 3 bed, which has l)een worked out 

 over the entire area of the vertical fault mentioned, .shows no trace of a break. 

 While this is suggestive of :i disconfoi luity, no s)n'fa<-e corroborations of such 

 an hiatus are .vet discov crcMl. 



The occurrence of tlic last pai :igr:ii)li is recalled wlieii one examines a break 

 in the Upper Me.saverde coal at Uogers, near Cerillos, .\ew Mexico. The upper 



" Inf rod'iced by C. K. I-cllli. 



XXXII— Blt.i,. Geol. See. Am., Vol. 26, 1014 



