GEOLOGY: W. H. BUCHER 
285 
The flora from Potosi is extensive and not yet fully elaborated. It 
includes about sixty species and the following genera are represented: 
Acacia, Acrostichiun, Amicia, Caesalpinia, CalHandra, Capparis, Cassia, 
Copaifera, Cuphea, Dalbergia, Desmodium, Drepanocarpus, Enterolo- 
bium, Escallonia, Euphorbia (?), Festuca, Gaylussacia, Gynrnogramme, 
(?), Hedysarum, Inga, Lomariopsis, Lonchocarpus, Machaerium, Mi- 
mosa, Mimosites, Myrica, Myrteola, Passiflora (?), Peltophorimi, Pithe- 
colobium, Platipodium, Poacites, Podocarpus, Polystichum, Porliera, 
Ruprechtia, Sweetia, Terminalia, and Weinmannia. 
A perusal of these genera, already recognized, is sufficient to convince 
any botanist or indeed any visitor to the region, that this flora is very- 
different from that now found in the Potosi region. While the botanical 
exploration of the present Bolivian flora leaves much to the future it 
is obvious that if we seek for representatives of this fossil flora in the 
recent flora of Bolivia, nearly all the genera are to be found represented 
in the more or less well watered country east of the present eastern range, 
and particularly on the lower eastern slopes. Moreover most of the fos- 
sil species are very close to still existing species of the latter region and 
this resemblance is so close that I cannot conceive of this flora being 
older than PHocene. 
There is then definite evidence that parts of the high plateau and of 
the eastern Cordillera stood at sea level in the late Tertiary. 
J Singewald, J. T. Jr., and Miller, B. L., Engin. Min. J., New York, 103, 1917, (171-176). 
^Engelhardt, H., Dresden, SUz-Ber. Isis, 1887, Abh. 5, (36), 7 figs.; Ibid., 1894, Abh. 
1, (1-13), 1 pi. 
3Britton, N. L., New York, Trans. Amer. Inst. Min. Engin., 21, 1893, (250-259). 
* Stille, H., Geol. Studien im Gebiete des Rio Magdalena, von Konen Festschrift, 1907, 
p. 356. 
LARGE CURRENT-RIFPLES AS INDICATORS OF PALEOGEOGRAPHY 
By Walter H. Bucher 
DEPARTMENT OF GEOLOGY. UNIVERSITY OF CINCINNATI 
Communicated by J. M. Clarke, January 28, 1917 
In the Eden and in parts of the Richmond Group (Upper Ordovician) 
large ripples, measuring 50 to 150 cm. from crest to crest, are rather 
common throughout the region of the Cincinnati Anticline, in Kentucky/ 
Indiana,^ and Ohio.''' From a careful study of very numerous rippled 
layers of these formations in southwestern Ohio and north-central 
Kentucky, of 13 rippled layers in the Brassfield formation of east-central 
Kentucky^ and of one in the Blackhand formation (Mississippian) of 
eastern Ohio,^^ the following data v/ere obtained: 
