Between this locality and the stone quarry 1/2 mile to south [B.O.V. 35-65 (6)(7)], all but basal foot ± of main bed and lower split have been channeled and ss above has thickened appreciably [from about 6' with clay split at loc. (8), to about between 35' at quarry. Thickness latter can be checked on map.] Clay above upper ss also in at loc. (1) B.O.V. 35-65, and looks fairly good & minable thickness. It is out completely at Helmer mine. To south it is thinner and more silty at Stone quarry; it is intermittently exposed south of here and probably continuous till cut off by fault north of Indian Creek. The S. branch Willow Creek locality is best exposure of unprospected clay seen in entire backyard S. of Golden. Area not now accessible by road, but trail in from Roxboro Pl Rd on Willow Creek Ranch passes along it on pediment surface. Access road from Helmer mine would be easy. Worth trenching is Dakota clay, Main bed and its ridlers, as well as lower split are all in here. 16,