True, Brandon. That's why I asked some geologists. They didn't necessarily agree with the author at the link because they understand that spherical concretions have been found elsewhere and are of different composition. They knew relatively little about any from Africa.
But if you want more, this is a difficult read for me, but the spheres are no mystery to experts either. I googled on "small spherical geologic concretions." This brief summary deals with some in Africa so they are not unknown.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6X-4KRY3VD-1&_user=10&_coverDate=02%2F01%2F2007&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=41710310a0b9ef06c0135926c4891ce4
This from the Handbook of Geological Terms, Geology and Physical Geography, I couldn't find the term pyrophylitte, but I did find this. I bring it up to make a point.
Pisolite, ...
These calcareous spherules are composed of concentric laminae, which commonly have a particle of sand, a fragment of shell or other organic substance as a nucleus. They owe their formation to the deposit of successive concretions around the included body while subjected to the action of water in which a rotary motion is induced; and the spheroids continue to increase until they become too heavy for further transport, and then subside, and are consolidated by subsequent infiltration . The springs near Carlsbad deposit,a beautiful pearly-looking pisolite, some portions of which are sufficiently compact to admit of being polished and manufactured into boxes and other ornaments.
Nature has a way of making things round or roundish if given time and the right conditions. These in particular have hollow centers. Different process, but from nature nonetheless.
http://en.wikipedia.org/wiki/Moeraki_Boulders
Then there's my Oklahoma pal who found one similar to that in Cremo's book. His old site is http://oklahomaproject.50megs.com/
If you click on page 1 of his Colbert Creek link to the right, scroll to the bottom photos, you'll see his. He calls his a Moqui Marble, found here at Wikipedia. Have to scroll down a bit.
http://en.wikipedia.org/wiki/Concretion
Point is, there are lots of things we don't know. Cremo makes some fascinating points in his book, but he obviously didn't do enough research on that particular set of rocks.