So what is it specifically that kept Indian corn cakes from rising? In a word: gluten. Corn meal simply hasn’t got any. As you may recall from previous posts on the subject, gluten is a substance that’s unique to wheat. It’s made up two proteins, gliadin and glutenin, which all by themselves are some of the longest protein molecules found in nature. Introduce water and agitate them a bit, and the glutenin molecules start bonding end-to-end, forming hugely long chains that intertwine with one another to make a mesh. That mesh is what allows dough to catch and hold the tiny bubbles of air and/or carbon dioxide that are the basis of leavening. When the bubbles heat, they fill with steam, which expands them to many, many times their original volume. As they expand, the stretchy gluten dough keeps them from escaping, and so the dough volume increases.
Where you have no gluten you have vastly fewer trapped bubbles. And Indian nokechicks being made from hand-hammered meal, would have had fewer still, since the odd sized grains would have created ample spaces from which steam could escape. Yes, the home-made ash leavening would have improved them somewhat, but not very much. In the end you would still have had a flat, hard, grainy little cake. And while that was perfectly acceptable to the Indians who had been making and enjoying them for millennia before the colonists ever arrived, to a pilgrim just stepping off the boat they were a fate (almost) worse than death.