Well, the following excerpts from Aelian's On Tactical Arrays of the Greeks don't solve all the riddles, but they are quite interesting. Note he mentions shock and charge quite often and his writing suggests there IS a lot of presumed contact being made here between infantry and cavalry. He mentions cavalry wedges breaking thru thinner phalanx ( yet of no concern as they broke "thru "air") too. Again, no where is it implied that the cavalry wont close to contact if the phalanx MERELY holds firm..... No suicide throwing horses on top of infantry either
, yet the amount of time spent explaining the tactics used to defend versus cavalry seems excessive if infantry just needed to stand there amd implies even pike phlanxs had to be wary ... take it for what it is, any spelling errors etc are mine as I could not find any copy on line that one can copy and paste.....
The phalanx antistomus is so called as it has two mouths or fronts. ……. Because the men posted in the middle of the battalion are placed back to back whilst those in the front or rear advance either way to meet the enemy, hence the phalanx takes the denomination which has been stated. This form of battle is of very great use to infantry when attacked by an enemy powerful in cavalry.
When cavalry are to charge infantry drawn up in this order of battle, the squadron takes a quadrilateral form, and is thrown into two oblong squares, or the kind that have their front twice as long as their depth , and which are employed at once against both fronts of the phalanx antistomus.
The phalanx Amphistomus resembles that mentioned in last chapter, and is adapted to resist varied charges of horse. Everything relative to the phalanx antistomus is applicable to this, with respect to either infantry or cavalry. In this particular, however, they differ, that in the phalanx antistomus, the charge is repelled by the external ranks in the front and rear, but in the phalanx amphistomus, by the flanks. In either instances the soldiers use long pikes like the Alani or Sauromatae. The amphistomus throws half the files to face the front, and half the rear, the men standing back to back. …….
That form of battle is called diphalangia antistomus, which in paragoge, or deduction, places the file leaders not on the external line, but draws them up facing inwards and fronting each other, half on the right, and half on the left.
This form is adopted when the cavalry charge in wedge, for the wedge having its acute angle in the leading point, with the flank commanders following in flank and endeavoring to break the front of the phalanx, the file leaders of foot, aware of their intention, throw themselves into the center for the purpose of resisting the charge, or suffering the wedge to pass thru between the grand divisions of the phalanx without hazarding the shock. The object of the wedge is to charge into the midst of the column and to overthow it. The leaders of the foot observing the point in which the charge is made, open, and standing like a wall on each hand, front inward and leave a void space for the wedge to pass thru.
A body of horse in this form is called by tacticians a wedge. It was invented by Phillip king of the Macedonians, who made its bravest men the leaders of the wedge, so they might be better defended and covered, and that he might more easily pierce the phalanx; just as in a spear, the shaper point makes way for the duller metal which forms the interior of the weapon
A squadron of horse forming an oblong square having its depth double that of its length is distinguished by the name heteromekes. … It is adapted to deceive the enemy by the narrowness of its front and to break his line by means of its weight and density of its construction. And it may be easily lead thru defiles…
The order of battle best opposed to this by infantry is the plagia phalanx or oblong battalion, which although it is easily pierced, yet the depth is so small that the violent charge of the horse is hardly felt by the foot, but expends itself on the air, because being extended lateral, the battalion is of small dimension from front to rear.