Hi gmatrant --

The way we look at it is that those specific words are used to introduce a fact that is surprising, based on two ideas that you would think contradict each other.

Here's an example:

"Although most people think of bats as flying rodents, they are actually more closely related to horses than to mice."

The purpose of "although" is to signal that we're talking about something that seems to be true, but is not. In this example, the "Although" phrase is stating something that people believe (but which is wrong); the second part then explains the reality of it, or the actual truth.

So in your example, if we break it apart, we get idea 1:

Clovis points are named after a specific place in New Mexico

and idea 2:

Clovis points are found all over North America

(The definition of what Clovis points are doesn't relate to this part of the discussion.)

The meaning of sentence is playing off of this: Many people might assume that something which is named after a place would only be found in that place. So, by combining these two ideas, you show the "surprising" part, in conjunction with the part that you'd assume to be true.

The "Even though" phrase (or "although" or "while") is a way to make the contrast.

Instead of the GMAC's phrase "appear to be logically incompatible", we might say "seem like they would not fit together" or maybe "on first glance, you'd think they would contradict each other."

Hope this helps!
EssaySnark