It was somewhere outside Barstow when "George" george@least wrote:

Drop nose, forward canard, low delta wing - yeah, right.

The XB70 didn't have a "delta wing" (beyond the level of something
vaguely triangular) - that was the whole point of it. The XB70's lift
came from a shock wave trapped under the lifting surface and retained
there by those huge downward-folding wingtips. This isn't the way that
any other aircraft (except a couple beginning with X) have flown and
certainly not the Tu144.

When the XB70 flew at low speed, with the wing working as a more
traditional wing, it was (to be honest) something of a dog. This was
one of the reasons the project was cancelled - it made a great
aircraft for an attacking dash at high speed, but loiter performance
was poor. And if you're going to build your deterrence around that
strategy, use missiles.

As to the canards, then canards have been a popular bodge since the
days of Santos Dumont. The Soviets used them because they didn't have
Aerospatiale's understanding of the aerodynamics of really high
performance deltas. It didn't need them at cruise - that's easy for a
delta, but retaining adequate control for a safe all-weather low-speed
landing envelope with a heavy delta aircraft is quite another matter.