  We consider a class of non-doubling manifolds $\mathcal{M}$ that are the
connected sum of a finite number of $N$-dimensional manifolds of the form
$\mathbb{R}^{n_{i}} \times \mathcal{M}_{i}$. Following on from the work of
Hassell and the second author \cite{hs2019}, a particular decomposition of the
resolvent operators $(\Delta + k^{2})^{-M}$, for $M \in \mathbb{N}^{*}$, will
be used to demonstrate that the vertical square function operator $$ Sf(x) :=
\left( \int^{\infty}_{0} \left|t \nabla (I + t^{2}
  \Delta)^{-M}f(x)\right|{2} \frac{dt}{t}\right)^{\frac{1}{2}} $$ is bounded on
$L^{p}(\mathcal{M})$ for $1 < p < n_{min} = \min_{i} n_{i}$ and weak-type
$(1,1)$. In addition, it will be proved that the reverse inequality $\left\Vert
f \right\Vert_{p} \lesssim \left\Vert S f\right\Vert_{p}$ holds for $p \in
(n_{min}',n_{min})$ and that $S$ is unbounded for $p \geq n_{min}$ provided $2
M < n_{min}$.
  Similarly, for $M > 1$, this method of proof will also be used to ascertain
that the horizontal square function operator $$ sf(x) :=
\left(\int^{\infty}_{0} \left|t^{2}\Delta (I + t^{2}
  \Delta)^{-M}f(x)\right|^{2} \, \frac{dt}{t}\right)^{\frac{1}{2}} $$ is
bounded on $L^{p}(\mathcal{M})$ for all $1 < p < \infty$ and weak-type $(1,1)$.
Hence, for $p \geq n_{min}$, the vertical and horizontal square function
operators are not equivalent and their corresponding Hardy spaces $H^p$ do not
coincide.
