lxxxvi THE PALEONTOLOGY OF MINNESOTA. 
EXPLANATION OF SECTIONS 1 TO 5. 
Nos. 1and 2. Sections of Black River group shales with the upper portion of the Stones River group and 
the lower bed of the Trenton group. 1 was taken at a locality between five and six miles south of Cannon Falls, 
Goodhue county; 2 at a point about one mile east of the same town. 
1. Vanuxemia bed of Stones River group. 
2. Stictoporella bed, consisting of soft shales and several layers of limestone. The latter are 
thin and largely made up of fossils, among them Stctoporella frondifera, Pachydictya foliata, Homotrypa 
minnesotensis, Anolotichia impolita and Rhynchotrema minnesotensis. 
3. Rhinidictya bed, consisting in the lower part almost entirely of soft, greenish shales, holding 
very few fossils. In the upper half or two-thirds there are numerous, more or less irregular, subcrystalline 
limestone plates, largely made up of fossil remains, chiefly Bryozoa, with Rhinidictya mutabilis very 
abundant. 
4 and 4a. Ctenodonta bed. In section 1 the lower four feet is a bed of dark shale in which no 
fossils were observed. The upper part contains five or six irregular layers of limestone, weathering red, 
which are filled with fossil shells, among them several species of Ctenodonta, Crytodonta tenella, C. affinis, 
Plethocardia umbonata, Whitella scofieldi, Matheria rugosa, and numerous Gastropoda and Cephalopoda 
The first layer contained, besides some of the species named, some plates of a large species of Carabocrinus, 
and in considerable abundance a slowly tapering tubular fossil, between one and two inches in length, 
that greatly resembles the Salterella billingsi which Safford regards as one of the most characteristic 
fossils of his “Central limestone’? in Tennessee. In section 5, the bed is thicker and the lower portion is 
less sharply distinguished from the upper. 
5and 5a. Phylloporina and Fucoid beds. These consist almost entirely of soft and highly 
fossiliferous, greenish shales. The fossils occur mostly in bands, and where they are most abundant they 
are often consolidated into rough limestone layers, rarely exceeding three inches in thickness.*. Bryozoa 
are exceedingly abundant in the Phylloporina bed, and as a rule in an excellent state of preservation. = Of 
the more striking and common forms we may mention Phylloporina corticosa, Trigonodictya conciliatria, 
Prasopora conoidea, Homotrypa tuberculata and Batostoma montuosum. In the Fucoid bed the fossils occur 
more sparingly, and the Bryozoa are wanting almost entirely. At the top there is a rough layer of impure 
limestone, a foot or more in thickness, which may be recognized at once by its rusty hue. It is sometimes 
divided into two or three layers, and when it contains any fossils at all they are always imperfect. 
6. This, the lowest or Clitambonites bed of the Trenton group, consists chiefly of yellowish 
shales. In the lower eight orten feet there are namerous irregular or nodular layers of impure limestone. 
These are very fossiliferous, and it is in this portion that such characteristic species of the bed as 
Clitambonites diversus, Strophomena scofieldi, Orthis meedsi, Prasopora insularis, Callopora ampla and 
Eridotrypa mutabilis are nearly always to be found. Near the middle of the bed Callopora goodhuensis and 
a small variety of Plectambonites sericea are very abundant. The upper seven or eight feet consist entirely 
of shale, and in this portion fossils are exceedingly rare. 
7. At the top of section 2, we recognized a small remnant of the Nematopora bed. 
Section 3, as exposed in an old road about two miles southeast from Cannon Falls. 
4. Ctenodonta bed. 
5. Phylloporina and Fucoid beds, both covered except at the base and top. 
6. Clitambonites bed. 6a, horizon of Clitambonites diversus; 6b, of Callopora goodhuensis 
6c, unfossiliferous shales. 
7. Nematopora bed. Drab to blue shales, including five or six layers of limestone, the latter 
very fossiliferous. Orthis meedsi var. germana, Homotrypa similis, Pachydictya pumila, Rhinidictya minima, 
Nematopora ovalis and N. granosa are both characteristic and common. At the point marked Ox some 
good specimens of Clitambonites diversus were obtained, while the shales immediately beneath it, when 
washed, afforded, beside the fossils above named, numerous minute Bryozoa of the genera Arthroclema 
and Helopora, and six species of Ostracoda. 
8. Lower part of Fusispira bed, here consisting entirely of gray shales, quite unfossiliferous 
except between twelve and fourteen feet above the base where about a dozen good specimens of Cyclospira 
bisulcata were found. 
Section 4, showing the whole of the Fusispira bed and the upper part of the Nematopora bed; Prosser’ s 
ravine near Wykoff, Fillmore county. 
: 1. Nematopora bed. - A layer of limestone two feet thick at the top. Obtained here Orthis 
meedsi var. germana, a variety of O. borealis, Platystrophia biforata, Strophomena trentonensis, Rafinesquina 
alternata, Rhynchotrema increbescens, and several undetermined Ostracoda and Bryzoa, the latter not well 
preserved. 
