41 surface to an anastomosing pattern, then to short elliptical cups and domes, and, in extreme cases, to small crescentic corrugations, elongated more or less perpendicular to the general direction of lineation. Such relationships may be seen south of Jim May Creek and east of the head of Cutbank Creek. Several outcrops in the Tenakihi Range show a second, much less distinct lineation. Where best observed the second lineation is approxi- mately parallel with the fold axes of the bedding (and schistosity), in- dependent of the direction of the more widespread lineation exhibited by corrugations lying in the foliation plane at an oblique angle to the fold axes. SCHISTOSITY All of the Tenakihi group rocks, except the purest quartzites, have a schistose or gneissic structure determined by the parallel orientation of mica and chlorite grains. The planes of schistosity or gneissosity are deformed into the small ‘lineation’ crumples previously described, but in any area larger than a few square inches, they are nearly always found to lie in large gentle folds almost exactly coinciding with bedding structures. Over many large areas, schistosity and bedding appear to be rigorously parallel; and in other areas the maximum angular difference between them is less than 5 degrees. In areas of relatively highly deformed rocks it has been observed that the schistosity is commonly less sharply contorted than the bedding. The general relations are such that the schistosity planes are parallel or very nearly parallel with the major bedding structures, ‘but cut across the bedding of the smaller folds, although exceptions to this generalization have been noted. The plane of schistosity thus reflects the large-scale structure of the anticlinoria in which the Tenakihi group rocks characteristically occur, but in many places bears no relation to minor contortions of bedding. GENERAL FOLD STRUCTURES The structures of individual beds in the Tenakihi group are dominated by the major northwest trending anticlinoria already mentioned, and minor folds can be recognized as local variations from this general pattern. The axis of each anticlinorium is curved and undulating, ranging from flat-lying to a northwest plunge of as much as 15 degrees; and the axial plane dips 55 to 70 degrees northeast. The individual folds forming the anticlinoria are for the most part open and gentle, and range from 500 feet to a mile or more from crest to crest. The anticlinorium on Chase Mountain and the area of Tenakihi group rocks in the north end of the Butler Range are believed to be connected by the overturned synclinorium in Tomias Lake Valley. The synclinorium appears to be essentially isoclinal between limbs about 7 miles apart. If this interpretation is correct, all the Tenakihi group rocks of the Butler Range in the map-area are overturned. ABNORMAL FOLD STRUCTURES In addition to the relatively regular, wave-like undulations forming the major, compound anticlines or anticlinoria of the Tenakihi group, there