The Jack's Reef Pentagonal is regarded as the un notched version of the Jack's Reef Corner Notch point. Here is Wm. Ritchie's description from his New York State typology guide. Like the corner notch form, these are Middle Woodland in age.
http://collections.nysm.nysed.gov/pr...entagonal.html
And a description from the Maryland typology guide:
Description from lithics-net:
This example is made from hornfels, one of many metavolcanics found in New England and procured for tool production. In the New England states, jasper, much of it from Pa., and hornfels were preferred materials. Jack Reef points of both forms tend to be very well made and the best materials available regionally were utilized, as well as imported jasper. Although this example might be confused for a resharpened Levanna, it originated at a Jack's Reef site and compares well to many other examples of this point type. See Ritchie's description for more photographed examples.
On the right, a hornfels Jack's Reef Pentagonal, which can be seen as an un notched form of a Jack's a Reef Corner-Notch on left, example also made of hornfels:
http://collections.nysm.nysed.gov/pr...entagonal.html
And a description from the Maryland typology guide:
Description from lithics-net:
This example is made from hornfels, one of many metavolcanics found in New England and procured for tool production. In the New England states, jasper, much of it from Pa., and hornfels were preferred materials. Jack Reef points of both forms tend to be very well made and the best materials available regionally were utilized, as well as imported jasper. Although this example might be confused for a resharpened Levanna, it originated at a Jack's Reef site and compares well to many other examples of this point type. See Ritchie's description for more photographed examples.
On the right, a hornfels Jack's Reef Pentagonal, which can be seen as an un notched form of a Jack's a Reef Corner-Notch on left, example also made of hornfels: